Note: This page contains sample records for the topic thin film superconductor from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Thin film superconductor magnetic bearings  

DOEpatents

A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

Weinberger, Bernard R. (Avon, CT)

1995-12-26

2

Thickness-dependent pinning in a superconductor thin film  

Microsoft Academic Search

The dependence of critical current density jc on film thickness (d) is calculated for the simple configuration of a semi-infinite finite-thickness superconductor film and a single vortex. This film-thickness dependence reflects the impact of vortex broadening in a thin film on its pinning by the films edge or an internal surface. The calculated film-thickness variation of jc in the range

D. Agassi; D. K. Christen; S. J. Pennycook

2007-01-01

3

Thickness-dependent pinning in a superconductor thin film  

Microsoft Academic Search

The dependence of critical current density jc on film thickness (d) is calculated for the simple configuration of a semi-infinite finite-thickness superconductor film and a single vortex. This film-thickness dependence reflects the impact of vortex broadening in a thin film on its pinning by the film's edge or an internal surface. The calculated film-thickness variation of jc in the range

D. Agassi; David K Christen; Stephen J Pennycook

2007-01-01

4

Growth and Characterization of Ferrite-High Temperature Superconductor Thin Films for Microwave Devices.  

National Technical Information Service (NTIS)

In an effort to integrate superconducting, conducting, ferrite and insulating thin films to produce microwave devices such as phase shifters and circulators, thin films (single and bi-layer) of ferrites (Strontium Hexaferrite, Fe3O4), superconductors (YBa...

R. J. Kennedy

2000-01-01

5

Thin film superconductors and process for making same  

DOEpatents

A process for the preparation of oxide superconductors from high-viscosity non-aqueous solution is described. Solutions of lanthanide nitrates, alkaline earth nitrates and copper nitrates in a 1:2:3 stoichiometric ratio, when added to ethylene glycol containing citric acid solutions, have been used to prepare highly viscous non-aqueous solutions of metal mixed nitrates-citrates. Thin films of these compositions are produced when a layer of the viscous solution is formed on a substrate and subjected to thermal decomposition.

Nigrey, P.J.

1988-01-21

6

Studies of Thin Film Hard Superconductors.  

National Technical Information Service (NTIS)

The preparation of superconducting V3Si films by sputter-deposition from V and Si targets is described. The dependence of critical current and magnetic field on deposition parameters is discussed. The operation of a novel rf sputtering system in which lin...

D. E. Anderson

1967-01-01

7

Theoretical studies of thin-film superconductors with pinning centers  

NASA Astrophysics Data System (ADS)

We investigate the effect of a ferromagnetic dot on a thin-film superconductor. We use a real-space method to solve the linearized Ginzburg-Landau equation in order to find the upper critical field, Hc3 . We show that Hc3 is crucially dependent on dot composition and geometry and may be significantly greater than Hc2 . Hc3 is maximally enhanced when: (1) the dot saturation magnetization is large, (2) the ratio of dot thickness to dot diameter is of order unity, and (3) the dot thickness is large. We also report on a study of vortex pinning in nanoscale antidot defect arrays in the context of the London theory. Using a wire network model, we discretize the array with a fine mesh, thereby providing a detailed treatment of pinning phenomena. We use Ewald's trick to efficiently calculate the vector potential of the supercurrent. The use of a fine grid has enabled us to examine both circular and elongated defects. We have given special attention to defects patterned in the form of a rhombus. The rhombic defects display pinning characteristics superior to circular defects constructed with the similar area. We calculate pinning potentials for defects containing zero and single quanta and we obtain a pinning phase diagram for the second matching field H = 2phio.

Cheng, Sa Lin

2001-07-01

8

Pseudogap in a thin film of a conventional superconductor.  

SciTech Connect

A superconducting state is characterized by the gap in the electronic density of states, which vanishes at the superconducting transition temperature T{sub c}. It was discovered that in high-temperature superconductors, a noticeable depression in the density of states, the pseudogap, still remains even at temperatures above T{sub c}. Here, we show that a pseudogap exists in a conventional superconductor, ultrathin titanium nitride films, over a wide range of temperatures above T{sub c}. Our study reveals that this pseudogap state is induced by superconducting fluctuations and favoured by two-dimensionality and by the proximity to the transition to the insulating state. A general character of the observed phenomenon provides a powerful tool to discriminate between fluctuations as the origin of the pseudogap state and other contributions in the layered high-temperature superconductor compounds.

Sacepe, B.; Chapelier, C.; Baturina, T. I.; Vinokur, V. M.; Baklanov, M. R.; Sanquer, M. (Materials Science Division); (CEA-INAC/UJF-Grenoble); (A.V. Rzhanov Inst. Semiconductor Physics); (IMEC)

2010-12-01

9

Pseudogap in a thin film of a conventional superconductor.  

PubMed

A superconducting state is characterized by the gap in the electronic density of states, which vanishes at the superconducting transition temperature T(c). It was discovered that in high-temperature superconductors, a noticeable depression in the density of states, the pseudogap, still remains even at temperatures above T(c). Here, we show that a pseudogap exists in a conventional superconductor, ultrathin titanium nitride films, over a wide range of temperatures above T(c). Our study reveals that this pseudogap state is induced by superconducting fluctuations and favoured by two-dimensionality and by the proximity to the transition to the insulating state. A general character of the observed phenomenon provides a powerful tool to discriminate between fluctuations as the origin of the pseudogap state and other contributions in the layered high-temperature superconductor compounds. PMID:21266990

Sacp, Benjamin; Chapelier, Claude; Baturina, Tatyana I; Vinokur, Valerii M; Baklanov, Mikhail R; Sanquer, Marc

2010-01-01

10

Size effect on the thermal conductivity of high-Tc thin-film superconductors  

Microsoft Academic Search

Using the kinetic theory approximation and reported data, this study shows that at low temperatures, the phonon mean free path in polycrystalline ceramic YBa2Cu3O7 can be of the order of the thickness of thin-film superconductors. In this case, boundary scattering reduces the thermal conductivity with decreasing film thickness. A simple method accounts for the size effect on conduction in thin

M. I. Flik; C. L. Tien

1990-01-01

11

Magnetic properties of thin films of soft superconductors  

Microsoft Academic Search

The torque method of measuring the magnetic properties of thin superconducting layers is discussed, and some results reported for experiments in which magnetic fields are applied parallel and perpendicular to the plane of evaporated films of tin, indium and indium-tin alloy. For the parallel case critical fields and supercooling fields can be measured. For the perpendicular case magnetization curves can

G. Robinson

1966-01-01

12

Single-target sputter deposition, post-processing and electron spectroscopy of perovskite superconductor thin films  

SciTech Connect

Thin films of Y-Ba-Cu-O superconductors were grown using a single-target DC diode sputtering technique. A variety of substrates were employed, including quartz, alumina, MgO, and strontium titanate. As-deposited films were amorphous. Formation of the superconducting structure was accomplished by post-deposition high-temperature anneals in oxygen. Deposition parameters leading to superconducting films from a single mixed-oxide target are discussed. Electron spectroscopy has been employed to non-destructively determine that the surface of the films are oxygen depleted, which may contribute to the high contact resistance measured in these films.

Han, Z.; Bourget, L.; Li, H.; Ulla, M.; Millman, W.S.; Baum, H.P.; Xu, M.F.; Sarma, B.K.; Levy, M.; Tonner, B.P.; and others

1988-02-25

13

Application of sol-gel techniques to thin-film superconductor systems  

SciTech Connect

This paper discusses the preparation and characterization of sol-gel produced thin films for barrier layer and high T{sub c} superconductor applications. Hydrolyzed metal alkoxide solutions were spin coated on Si substrates with subsequent thermal processing. Barrier layers of alkaline earth oxides, perovskites, Y{sub 2}O{sub 3}, ZrO{sub 2} and others were produced. Characterization was performed via SEM, XRD, ESCA, Auger depth profiling and four point probe resistivity measurements for 1-2-3 thin films. On Si wafers, barrier layer films were fairly smooth with some cracking and pitting present. Si migration was severe for alkaline earth thin films on Si wafers. Some perovskite films on Si showed formation of Ba-Si-O phases at the Si interface.

Wandass, J.H.; Cambria, F.M.; Whitwell, G.E. (Akzo Chemicals Inc., Akzo Research Laboratory Dobbs Ferry, Livingston Ave., Dobbs Ferry, NY (USA))

1990-01-25

14

Highly Sensitive Infrared Detector Fabricated with Thin Film of High Tc Y-Ba-Cu-O Superconductor. Phase 1.  

National Technical Information Service (NTIS)

In the phase I study of the project entitled 'Highly Sensitive Infrared Detector Fabricated with Thin Film of High Tc Y-Ba-Cu-O Superconductor using Pulsed Laser', we have successfully deposited thin films of Y-Ba-Cu-O on MgO/TcO2 substrate by plasma assi...

R. Rao

1989-01-01

15

Vortices in a thin-film superconductor with a spherical geometry  

Microsoft Academic Search

We report results from Monte Carlo simulations of a thin film superconductor\\u000ain a spherical geometry within the lowest Landau level approximation. We\\u000aobserve the absence of a phase transition to a low temperature vortex solid\\u000aphase with these boundary conditions; the system remains in the vortex liquid\\u000aphase for all accessible temperatures. The correlation lengths are measured for\\u000aphase

M. J. W. Dodgson; M. A. Moore

1997-01-01

16

Simulation of below-gap photoresponse of thin-film superconductors by Josephson-junction arrays  

Microsoft Academic Search

The below-gap, nonbolometric photoresponse of granular, thin-film superconductors seen recently by Strom et al. and by other experimental groups is simulated by a numerical study of the dc voltage response to an applied ac current at finite temperature, by ordered and disordered two-dimensional arrays of resistively shunted Josephson junctions. The current-assisted random generation of vortex-antivortex pairs by the temperature fluctuations

Y. Cai; P. L. Leath; Z. Yu

1994-01-01

17

Field-induced reentrant superconductivity in thin films of nodal superconductors  

NASA Astrophysics Data System (ADS)

Previous work on nodal d-wave superconductors has shown that a Fulde-Ferrell-Larkin-Ovchinnikov- (FFLO-) like superconducting (SC) state, which is modulated along the film plane, can be realized with no magnetic field when quasiparticles acquire an additional linear term in the wave vector in their dispersion. In the present work, the stability of such a modulated SC state in an artificial film against an applied magnetic field is studied. As a reflection of the presence of two FFLO-like states of different origins, one close to zero field and the other at the high-field end, in a single field vs temperature phase diagram of thin films, the conventional SC state, which is uniform along the film plane, generally tends to appear as a reentrant ordered phase bounded by the normal phase in lower fields.

Hachiya, M.; Aoyama, K.; Ikeda, R.

2013-08-01

18

A novel method for characterization of superconductors: Physical measurements and modeling of thin films  

NASA Technical Reports Server (NTRS)

A method for characterization of granular superconducting thin films has been developed which encompasses both the morphological state of the sample and its fabrication process parameters. The broad scope of this technique is due to the synergism between experimental measurements and their interpretation using numerical simulation. Two novel technologies form the substance of this system: the magnetically modulated resistance method for characterizing superconductors; and a powerful new computer peripheral, the Parallel Information Processor card, which provides enhanced computing capability for PC computers. This enhancement allows PC computers to operate at speeds approaching that of supercomputers. This makes atomic scale simulations possible on low cost machines. The present development of this system involves the integration of these two technologies using mesoscale simulations of thin film growth. A future stage of development will incorporate atomic scale modeling.

Kim, B. F.; Moorjani, K.; Phillips, T. E.; Adrian, F. J.; Bohandy, J.; Dolecek, Q. E.

1993-01-01

19

Thin film growth of the 2122-phase of BCSCO superconductor with high degree of crystalline perfection  

NASA Technical Reports Server (NTRS)

Thin films of the 80 K-phase of BiCaSrCu-oxide superconductor having the composition of Bi2Ca1.05Sr2.1Cu2.19O(x) and high degree of crystalline perfection have been grown on c-axis oriented twin free single crystal substrates of NdGaO3. This has been achieved by carefully establishing the growth conditions of the LPE experiments. The temperature regime of 850 to 830 C and quenching of the specimens on the termination of the growth period are found to be pertinent for the growth of quasi-single crystalline superconducting BCSCO films on NdGaO3 substrates. The TEM analysis reveals a single crystalline nature of these films which exhibit 100 percent reflectivity in infrared regions at liquid nitrogen temperature.

Raina, K. K.; Narayanan, S.; Pandey, R. K.

1992-01-01

20

Thin-film superconductor in an exchange field  

SciTech Connect

Using the technique of spin-polarized tunneling, we studied tunnel junctions with EuS/Al bilayer electrodes. We found a large effective internal field in the Al film, which gives rise to extra Zeeman splitting in the superconducting quasiparticle density of states and which is attributed to the exchange interaction between the Eu ions and the Al conduction electrons. This exchange field, acting only on the electron spins, is inversely proportional to the thickness of the Al, causes no observable orbital depairing in the Al, and leads to a first-order transition to the normal state.

Hao, X.; Moodera, J.S.; Meservey, R. (Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts (USA))

1991-09-02

21

Superconductor-Metal-Insulator transition in two dimensional Ta thin Films  

NASA Astrophysics Data System (ADS)

Superconductor-insulator transition has been induced by tuning film thickness or magnetic field. Recent electrical transport measurements of MoGe, Bi, Ta thin films revealed an interesting intermediate metallic phase which intervened superconducting and insulating phases at certain range of magnetic field. Especially, Ta thin films show the characteristic IV behavior at each phase and the disorder tuned intermediate metallic phase [Y. Li, C. L. Vicente, and J. Yoon, Physical Review B 81, 020505 (2010)]. This unexpected metallic phase can be interpreted as a consequence of vortex motion or contribution of fermionic quasiparticles. In this presentation, we report the scaling behavior during the transitions in Ta thin film as well as the transport measurements in various phases. Critical exponents v and z are obtained in samples with wide ranges of disorder. These results reveal new universality class appears when disorder exceeds a critical value. Dynamical exponent z of Superconducting sample is found to be 1, which is consistent with theoretical prediction of unity. z in a metallic sample is suddenly increased to be approximately 2.5. This critical exponent is much larger than the value found in other system and theoretical prediction.

Park, Sun-Gyu; Kim, Eunseong

2013-03-01

22

Shape resonances and shell effects in thin-film multiband superconductors  

NASA Astrophysics Data System (ADS)

We study analytically the evolution of superconductivity in clean quasi-two-dimensional multiband superconductors as the film thickness enters the nanoscale region by mean-field and semiclassical techniques. Tunneling into the substrate and finite lateral size effects, which are important in experiments, are also considered in our model. As a result, it is possible to investigate the interplay between quantum coherence effects, such as shape resonances and shell effects, with the potential to enhance superconductivity, and the multiband structure and the coupling to the substrate that tend to suppress it. The case of magnesium diboride, which is the conventional superconductor with the highest critical temperature, is discussed in detail. Once the effect of the substrate is considered, we still observe quantum size effects such as the oscillation of the critical temperature with the thickness but without a significant enhancement of superconductivity. In thin films with a sufficiently longer superconducting coherence length, it is, however, possible to increase the critical temperature above the bulk limit by tuning the film thickness or lateral size.

Romero-Bermdez, Aurelio; Garca-Garca, Antonio M.

2014-01-01

23

Optical properties of TiN thin films close to the superconductor-insulator transition  

NASA Astrophysics Data System (ADS)

We present the intrinsic optical properties over a broad spectral range of TiN thin films deposited on an Si/SiO2 substrate. We analyze the measured reflectivity spectra of the film-substrate multilayer structure within a well-establish procedure based on the Fresnel equation and extract the real part of the optical conductivity of TiN. We identify the metallic contribution as well as the finite energy excitations and disentangle the spectral weight distribution among them. The absorption spectrum of TiN bears some similarities with the electrodynamic response observed in the normal state of the high-temperature superconductors. Particularly, a mid-infrared feature in the optical conductivity is quite reminiscent of a pseudogap-like excitation.

Pfuner, F.; Degiorgi, L.; Baturina, T. I.; Vinokur, V. M.; Baklanov, M. R.

2009-11-01

24

Evaluation of AC Losses in High Superconductor Thin Film by Element-Free Galerkin Method and Double Exponential Formula  

Microsoft Academic Search

AC loses in high superconductor (HTS) thin film are evaluated by element-free Galerkin method with double exponential formula. The shielding current density in an HTS is necessary information to calculate the AC loss. Formulation of the electromagnetic behavior of the shielding current density gives a system. However, improper integrals appear as coefficients of the system and the integrand have a

Soichiro Ikuno; Teruou Takayama; Atsushi Kamitani

2008-01-01

25

High-frequency applications of high-temperature superconductor thin films  

NASA Astrophysics Data System (ADS)

High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz.

Klein, N.

2002-10-01

26

Thin film growth and characterization of the electron-doped superconductor samarium cerium copper oxide  

NASA Astrophysics Data System (ADS)

Sm2-xCexCuO 4-y belongs to a class of materials known as electron-doped superconductors (Ln2- xMxCuO4- y; Ln = Pr, Nd, Sm, Eu; M = Ce, Th) and has a moderately high superconducting critical temperature, Tc, of 20 K at optimal doping (x = 0.15). The trivalent rare earth site is doped with tetravalent Ce or Th; hence the name "electron-doped". Sm2- xCexCuO4- y also exhibits a unique magnetic structure at low temperatures (T < 6 K) due to the antiferro-magnetic ordering of the Sm3+ ions. In this study, thin films of the electron-doped superconductor Sm 2-xCexCuO 4-y (SCCO) have been grown by pulsed laser deposition (PLD) for a cerium concentration range of x = 0.13 to x = 0.19. The films have been characterized through x-ray diffraction, electrical transport, and thermal transport measurements. A temperature versus cerium content (T-x) phase diagram has been constructed from the electrical transport measurements and yields a superconducting region similar to that of two of the other electron-doped superconductors Nd2-xCe xCuO4-y and Pr 2-xCexCuO 4-y. Thermopower measurements were also performed on the samples and show a dramatic change from the under-doped region (x < 0.15) to the overdoped region (x > 0.15). Additionally, the standard Fisher-Fisher-Huse (FFH) vortex glass scaling model has been applied to the magnetoresistance data, as well as a modified scaling model (RRA), and the analysis yields values of the vortex glass melting temperature, T g, and critical exponent, nu(z-1). A magnetic field versus temperature (H-T) phase diagram has been constructed for the films with cerium content x ? 0.14, displaying the vortex glass melting lines. Magnetoresistance data taken as a function of angle, theta, is also discussed in the context of the vortex glass scaling model.

Scanderbeg, Daniel Joseph

27

Peak-effect, a new phenomenon observed at microwave frequencies in high Tc superconductor thin films  

NASA Astrophysics Data System (ADS)

Measurements of microwave surface resistance in magnetic fields (parallel to c-axis), ranging between 0.2 and 0.9 T, of high quality epitaxial DyBa 2Cu 3O 7- y and YBa 2Cu 3O 7- y superconducting thin films show a pronounced peak near the superconducting transition temperature. It is more pronounced at a frequency of 9.55 GHz as compared to 4.88 GHz. The exact nature of the peak is somewhat sample-dependent thereby indicating that the nature and distribution of defects in the films or the pinning sites determine the nature of the peaks; however, it follows the general trend that as the magnetic field is increased the peak shifts towards the lower temperature and is absent when the field is zero. The temperature and field dependence of the peak suggests that this peak could be associated with the order-disorder transition of the flux-line lattice. The peak-effect shows strong frequency dependence close to the depinning frequency of the flux line lattice. We explain our data in terms of the temperature dependence of the Labusch parameter within the collective pinning scenario in type II superconductors.

Bhangale, A. R.; Banerjee, T.; Raychaudhuri, P.; Pai, S. P.; John, J.; Bhagwat, S. S.; Bagwe, V. C.; Shirodkar, V. S.; Pinto, R.

2002-11-01

28

Thin film growth of Fe-based superconductors: from fundamental properties to functional devices. A comparative review.  

PubMed

Fe-based superconductors bridge a gap between MgB2 and the cuprate high temperature superconductors as they exhibit multiband character and transition temperatures up to around 55 K. Investigating Fe-based superconductors thus promises answers to fundamental questions concerning the Cooper pairing mechanism, competition between magnetic and superconducting phases, and a wide variety of electronic correlation effects. The question addressed in this review is, however, is this new class of superconductors also a promising candidate for technical applications? Superconducting film-based technologies range from high-current and high-field applications for energy production and storage to sensor development for communication and security issues and have to meet relevant needs of todays society and that of the future. In this review we will highlight and discuss selected key issues for Fe-based superconducting thin film applications. We initially focus our discussion on the understanding of physical properties and actual problems in film fabrication based on a comparison of different observations made in the last few years. Subsequently we address the potential for technological applications according to the current situation. PMID:24695004

Haindl, S; Kidszun, M; Oswald, S; Hess, C; Buchner, B; Kolling, S; Wilde, L; Thersleff, T; Yurchenko, V V; Jourdan, M; Hiramatsu, H; Hosono, H

2014-04-01

29

XPS studies of Cu1-xTlxBa2Ca2Cu3O10-y superconductor thin films  

Microsoft Academic Search

X-ray photoemission spectroscopy (XPS) of Cu1-xTlxBa2Ca2Cu3O10-delta (Cu1-xTlx-1223) superconductors thin films is studied. These films were prepared by amorphous phase epitaxy method on the SrTiO3 substrate. This compound has Cu1-xTlxBa2O4-delta charge reservoir layer and three CuO2 planes. The atoms in the CuO2 planes have strong covalent bonding, while the some of the atoms in Cu1-xTlxBa2O4-delta charge reservoir, such as oxygen (Odelta)

Nawazish A. Khan; A. A. Khurram; K. Sabeeh; Azam Iraji-Zad; M. M. Ahadian

2005-01-01

30

XPS studies of Cu 1? x Tl x Ba 2Ca 2Cu 3O 10? y superconductor thin films  

Microsoft Academic Search

X-ray photoemission spectroscopy (XPS) of Cu1?xTlxBa2Ca2Cu3O10?? (Cu1?xTlx-1223) superconductors thin films is studied. These films were prepared by amorphous phase epitaxy method on the SrTiO3 substrate. This compound has Cu1?xTlxBa2O4?? charge reservoir layer and three CuO2 planes. The atoms in the CuO2 planes have strong covalent bonding, while the some of the atoms in Cu1?xTlxBa2O4?? charge reservoir, such as oxygen (O?)

Nawazish A. Khan; A. A. Khurram; K. Sabeeh; Azam Iraji-zad; M. M. Ahadian

2005-01-01

31

Low-loss substrate for epitaxial growth of high-temperature superconductor thin films  

Microsoft Academic Search

A perovskite-like single-crystal substrate material has been investigated that simultaneously permits epitaxial growth of 1-2-3 superconductor films and possesses desirable rf properties of low dielectric constant and loss tangent. The lattice constant of 3.792 A? provides a lattice match to within 1% of the a axis of 1-2-3. Sputtered films of erbium-barium-copper-oxide have been produced on (100) LaAlO3 substrates that

R. Wo Simon; C. E. Platt; A. E. Lee; G. S. Lee; K. P. Daly; M. S. Wire; J. A. Luine; M. Urbanik

1988-01-01

32

Fabrication of high T(sub c) superconductor thin film devices: Center director's discretionary fund  

NASA Technical Reports Server (NTRS)

This report describes a technique for fabricating superconducting weak link devices with micron-sized geometries etched in laser ablated Y1Ba2Cu3O(x) (YBCO) thin films. Careful placement of the weak link over naturally occurring grain boundaries exhibited in some YBCO thin films produces Superconducting Quantum Interference Devices (SQUID's) operating at 77 K.

Sisk, R. C.

1992-01-01

33

Thin films  

NSDL National Science Digital Library

This simulation illustrates the behavior of thin films for reflected light. The user can change the angle of the incident beam, the thickness of the thin film and the type of thin film used. Two types of thin film are allowed.

Renault, Pascal

2009-12-04

34

Phase diagram of multiply connected superconductors: A thin-wire loop and a thin film with a circular hole  

Microsoft Academic Search

The phase diagram of a thin superconducting film with a circular hole in axial magnetic field is presented. The result is obtained by solving numerically the nonlinear Ginzburg-Landau (GL) equation in the limit of a thin film with large kappaeff=lambdaeff\\/xi (where lambdaeff=lambda2\\/d is the effective screening length for a film of thickness d). First-order phase transitions between localized (around the

A. Bezryadin; A. Buzdin; B. Pannetier

1995-01-01

35

Method for forming single phase, single crystalline 2122 BCSCO superconductor thin films by liquid phase epitaxy  

NASA Technical Reports Server (NTRS)

A substantially single phase, single crystalline, highly epitaxial film of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor which has a T.sub.c (zero resistance) of 83 K is provided on a lattice-matched substrate with no intergrowth. This film is produced by a Liquid Phase Epitaxy method which includes the steps of forming a dilute supercooled molten solution of a single phase superconducting mixture of oxides of Bi, Ca, Sr, and Cu having an atomic ratio of about 2:1:2:2 in a nonreactive flux such as KCl, introducing the substrate, e.g., NdGaO.sub.3, into the molten solution at 850.degree. C., cooling the solution from 850.degree. C. to 830.degree. C. to grow the film and rapidly cooling the substrate to room temperature to maintain the desired single phase, single crystalline film structure.

Pandey, Raghvendra K. (Inventor); Raina, Kanwal (Inventor); Solayappan, Narayanan (Inventor)

1994-01-01

36

Possibility in thin film device applications of some new superconductors (Invited)  

Microsoft Academic Search

In the electronic device applications of superconductors, there has been noticeable progress in the studies on superconducting large-scale integrated logic circuits using single flux quantum devices. In these circuit fabrications, REBa2Cu3O7-? (RE: rare earth elements) SNS (superconductor\\/normal-metal\\/superconductor) tunnel junctions are used in addition to Nb-based SIS (superconductor\\/insulator\\/superconductor) Josephson junctions. Here we report on the following three superconductors recently found, which

Shugo Kubo

2001-01-01

37

Effect of ferromagnetic film thickness on magnetoresistance of thin-film superconductor-ferromagnet hybrids  

NASA Astrophysics Data System (ADS)

We study the influence of the thickness Df of the plain ferromagnetic (F) film on the electrical resistance of the flux-coupled hybrids, consisting of superconducting (S) Al film and multilayer [Co/Pt] F film with out-of-plain magnetization. The behavior of such hybrids at high and low temperatures is found to be different as follows: the nucleation of superconductivity at high temperatures is governed mainly by the typical lateral dimensions of the magnetic domains, while low-temperature properties are determined by topology of the magnetic template. We show that an increase in the Df value leads to a broadening of the field-intervals and temperature intervals where nonmonotonous dependence of the superconducting critical temperature Tc on the applied magnetic field H is observed (for demagnetized F films). Further increase in the Df value results in a global suppression of superconductivity. Thus, we determined an optimal thickness, when the nonmonotonous dependence Tc(H) can be observed in rather broad T and H range, what can be interesting for further studies of the localized superconductivity in planar Al-based S/F hybrids and for development of the devices which can exploit the localized superconductivity.

Aladyshkin, A. Yu.; Volodin, A. P.; Moshchalkov, V. V.

2010-08-01

38

From molecule-based (super)conductors to thin films, nanowires and nanorings  

Microsoft Academic Search

Thin films of (TTF)(TCNQ) (TTF=tetrathiafulvalene, TCNQ=tetracyanoquinodimethane) are deposited on Si (001), KBr, and stainless steel conversion coatings (SSCC) using chemical vapor deposition. These films are characterized by IR, XRD, conductivity measurements, and SEM. Conducting nanowires and nanorings of (TTF)(TCNQ) and nanowires of (TTF)[Ni(dmit) 2 ] 2 (typically, 20 nm20 ?m) are prepared by successively dipping SSCC in acetonitrile solutions of

Patrick Cassoux; Dominique De Caro; Lydie Valade; Hlne Casellas; Barbara Daffos; Maria Elena Sanchez Vergara

2003-01-01

39

The influence of external factors on the corrosion resistance of high temperature superconductor thin films against moisture  

NASA Astrophysics Data System (ADS)

High temperature superconductor (HTS) thin films have been systematically investigated for their corrosion resistance against moisture by studying the role of external factors such as temperature (T), relative humidity (RH), and the type of substrates in the corrosion. In general, (i) the corrosion is progressed monotonously with increasing T as well as RH, (ii) a threshold level of water vapor is needed to cause degradation, and (iii) between T and RH, the influence of T is more dominant. HTS films on SrTiO3 and CeO2 buffered sapphire (cbs) substrates showed better corrosion stability and a low rate of degradation in the critical current density as compared to that of the film grown on MgO substrate. Between DyBa2Cu3Oz (DBCO) and YBa2Cu3Oz, the former is reproducibly found to have many fold higher corrosion resistance against moisture. This observed enhancement in the corrosion resistance in DBCO could be explained by the improved microstructure in the films and the better lattice matching with the substrate. Thus, the dual advantage of DBCO/cbs films, i.e., the enhanced corrosion stability of DBCO and the appropriate dielectric properties of sapphire, can be readily exploited for the use of DBCO/cbs films in the microwave and power devices.

Murugesan, M.; Obara, H.; Yamasaki, H.; Kosaka, S.

2006-12-01

40

Thin film seeds for melt processing textured superconductors for practical applications  

DOEpatents

A method of fabricating bulk superconducting material such as RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} where R is La or Y comprising depositing a thin epitaxially oriented film of Nd or Sm (123) on an oxide substrate is disclosed. The powder oxides of RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} or oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}, where R is Y or La are heated, in physical contact with the thin film of Nd or Sm (123) on the oxide substrate to a temperature sufficient to form a liquid phase in the oxide or carbonate mixture while maintaining the thin film solid to grow a large single domain 123 superconducting material. Then the material is cooled. The thin film is between 200 {angstrom} and 2000 {angstrom}. A construction prepared by the method is also disclosed.

Veal, B.W.; Paulikas, A.; Balachandran, U.; Zhong, W.

1999-02-09

41

Thin film seeds for melt processing textured superconductors for practical applications  

DOEpatents

A method of fabricating bulk superconducting material such as RBa.sub.2 Cu.sub.3 O.sub.7-.delta. where R is La or Y comprising depositing a thin epitaxially oriented film of Nd or Sm (123) on an oxide substrate. The powder oxides of RBa.sub.2 Cu.sub.3 O.sub.7-.delta. or oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa.sub.2 Cu.sub.3 O.sub.7-.delta., where R is Y or La are heated, in physical contact with the thin film of Nd or Sm (123) on the oxide substrate to a temperature sufficient to form a liquid phase in the oxide or carbonate mixture while maintaining the thin film solid to grow a large single domain 123 superconducting material. Then the material is cooled. The thin film is between 200 .ANG. and 2000 .ANG.. A construction prepared by the method is also disclosed.

Veal, Boyd W. (Downers Grove, IL); Paulikas, Arvydas (Downers Grove, IL); Balachandran, Uthamalingam (Hinsdale, IL); Zhong, Wei (West Lafayette, IN)

1999-01-01

42

ac inductance measurements of thin superconductors and ferromagnets: Demagnetization effects  

SciTech Connect

Measurements of magnetic properties of thin-film superconductors at 77 K using dc magnetic fields and ac inductance techniques are discussed. The effects of demagnetizing fields on these measurements are analyzed and compared with results for thin ferromagnets. It is shown that for perpendicular magnetic fields opposite effects are predicted and observed for ferromagnets as compared to superconductors.

Flippen, R.B. (Central Research and Development, E.I. Du Pont de Nemours and Co., Inc., P.O. Box 80228, Wilmington, Delaware (USA))

1991-10-01

43

Sequentially evaporated thin Y-Ba-Cu-O superconductor films: Composition and processing effects  

NASA Technical Reports Server (NTRS)

Thin films of YBa2Cu3O(7-beta) have been grown by sequential evaporation of Cu, Y, and BaF2 on SrTiO3 and MgO substrates. The onset temperatures were as high as 93 K while T sub c was 85 K. The Ba/Y ratio was varied from 1.9 to 4.0. The Cu/Y ratio was varied from 2.8 to 3.4. The films were then annealed at various times and temperatures. The times ranged from 15 min to 3 hr, while the annealing temperatures used ranged from 850 C to 900 C. A good correlation was found between transition temperature (T sub c) and the annealing conditions; the films annealed at 900 C on SrTiO3 had the best T sub c's. There was a weaker correlation between composition and T sub c. Barium poor films exhibitied semiconducting normal state resistance behavior while barium rich films were metallic. The films were analyzed by resistance versus temperature measurements and scanning electron microscopy. The analysis of the films and the correlations are reported.

Valco, George J.; Rohrer, Norman J.; Warner, Joseph D.; Bhasin, Kul B.

1988-01-01

44

Substrate effect on thermal stability of superconductor thin films in the peritectic melting.  

PubMed

Systematic experiments were performed by in situ observation of the YBa(2)Cu(3)O(z) (Y123 or YBCO) melting. Remarkably, the superheating phenomenon was identified to exist in all commonly used YBCO thin films, that is, films deposited on MgO, LaAlO(3) (LAO), and SrTiO(3) (STO) substrates, suggesting a universal superheating mode of the YBCO film. Distinctively, YBCO/LAO films were found to possess the highest level of superheating, over 100 K, mainly attributed to the lattice match effect of LAO substrate, that is, its superior lattice fit with Y123 delaying the Y123 dissolving and inferior lattice matching with Y(2)BaCuO(5) (Y211) delaying the Y211 nucleation. Moreover, strong dependence of the thermal stability on the substrate material for Y123 films was also found to be associated with the substrate wettability by the liquid and the potential element doping from the substrate. Most importantly, the understanding of the superheating behavior is widely valid for more film/substrate constructions that have the same nature as the YBCO film/substrate. PMID:22540312

Chen, Y Y; Fang, T F; Yan, S B; Yao, X; Tao, B W

2012-05-31

45

Low-loss substrate for epitaxial growth of high-temperature superconductor thin films  

SciTech Connect

A perovskite-like single-crystal substrate material has been investigated that simultaneously permits epitaxial growth of 1-2-3 superconductor films and possesses desirable rf properties of low dielectric constant and loss tangent. The lattice constant of 3.792 A provides a lattice match to within 1% of the a axis of 1-2-3. Sputtered films of erbium-barium-copper-oxide have been produced on (100) LaAlO/sub 3/ substrates that exhibit sharp resistive transitions at 90 K (..delta..T = 1K), bulk superconductivity as determined by ac susceptibility measurements, and nearly single-crystal growth as evidenced by x-ray diffraction and high-resolution scanning electron microscopy. The high-frequency dielectric properties of LaAlO/sub 3/ were experimentally investigated at several temperatures. The low-frequency dielectric constant was measured to be 15 and the microwave loss tangent ranged from 6 x 10/sup -4/ at room temperature to 5 x 10/sup -6/ at 4 K.

Simon, R.W.; Platt, C.E.; Lee, A.E.; Lee, G.S.; Daly, K.P.; Wire, M.S.; Luine, J.A.; Urbanik, M.

1988-12-26

46

A New Technique for Studying the Pinning Force on a Single Vortex in a Thin-Film Superconductor  

NASA Astrophysics Data System (ADS)

We have developed a new SQUID-based technique for studying the pinning of a single vortex in a superconducting thin film patterned into a cross shape. Ends of each strip are connected via superconducting wires to the input coils of two SQUIDs, forming superconducting inductive loops. The vortex is trapped by heating the intersection of the cross above its critical temperature with a laser pulse.(G.S. Park, C.E. Cunningham, B. Cabrera, and M.E. Huber, J. Appl. Phys. 73 (1993) 2419.) The vortex is detected and its position measured by a shift in the quantization currents in the loops coupled to the SQUIDs. This technique provides a combination of good temporal and spatial resolution of the vortex position. By sending currents through both strips, we can exert on the vortex a Magnus force in any direction, and we can detect its motion in the superconductor with the SQUIDs. We are using this technique to study flux motion between pinning sites and to measure the temperature-dependence of the pinning force in thin-film niobium.

Cunningham, Charles E.; de Young, Tyce; Cochran, Matthew; Rinehart, Adam; Peterson, Sarah; Andrews, Timothy

1998-03-01

47

The use of BaF sub 2 buffer layers for the sputter-deposition of TlCaBaCuO thin-film superconductors  

SciTech Connect

Thin films of the Tl-based superconductors often have relatively poor properties because of film/substrate interdiffusion which occurs during the anneal. We have therefore investigated the use of BaF{sub 2} as a diffusion barrier. TlCaBaCuO thin films were deposited by dc magnetron sputtering onto MgO <100> substrates, both with and without an evaporation-deposited BaF{sub 2} buffer layer, and post-annealed in a Tl over-pressure. Electrical properties of the films were determined by four-point probe analysis, and compositions were measured by ion-backscattering spectroscopy. Structural analysis was performed by x-ray diffraction and scanning electron microscopy. The BaF{sub 2} buffer layers were found to significantly improve the properties of the TlCaBaCuO thin films. 8 refs., 3 figs.

Hubbard, K.M.; Arendt, P.N.; Brown, D.R.; Cooke, D.W.; Elliott, N.E.; Farr, J.D.; Nastasi, M.; Ott, K.C.; Peterson, E.J.; Reeves, G.A.

1989-01-01

48

Critical field measurements on very thin films of V-Ga superconductors  

SciTech Connect

V/sub 3/Ga thin films, 500, 20, 10 and 8 nm thick have been made for the purpose of studying the role of spin-orbit scattering in the theory of high field superconductivity. Either 1% dopings or thin layers of high-atomic-number elements have been added to these samples in an attempt to increase the spin-orbit scattering rate in this paramagnetically limited material. Critical fields are presented and material parameters are obtained by fitting to a modified Werthamer-Helfand-Hohenberg (WHH) theory. The uniqueness of the parameters obtained in this manner is discussed in light of Fermi-liquid effects. Comparisons are drawn with bulk V/sub 3/Ga.

Tkaczyk, J.E.; Tedrow, P.M.

1985-01-01

49

In situ growth of high temperature superconductor thin films with evaporation techniques using an ozone jet  

SciTech Connect

This paper reports on high quality YBa{sub 2}Cu{sub 3}O{sub 7} thin films grown in situ on various substrates (SrTiO{sub 3}, Al{sub 2}O{sub 3}, Si) using MBE techniques and an ozone jet. The yttrium and copper are evaporated from electron gun sources and the barium is evaporated from a Knudsen cell. All sources are controlled by a single mass spectrometer feedback system to obtain the correct fluxes at high partial ozone pressures. During deposition the partial ozone pressure at the substrate position is estimated to be 10{sup {minus}3}-10{sup {minus}2} mbar. The substrate holder temperature is 700{degrees} C. The real substrate temperature is estimated to be lower than 650{degrees} C. The films are analyzed with R(T), X-ray diffraction and RBS measurements. SEM photographs are taken of the surface.

Applebloom, H.M.; Aolriaanse, J.P.; Fortuin, A.W.; deGroot, H.I.; Verbrugh, S.M.; Rietveld, G.; Hadley, P.; van der Marel, D.; Mooij, J.E. (Faculty of Applied Physics, Delft Univ. of Technology, P.O. Box 5046, 2600 GA Delft (NL))

1991-03-01

50

Processing and characterization of high temperature superconductor thin films deposited by electron beam co-evaporation  

NASA Astrophysics Data System (ADS)

Ever since the high temperature superconductors (HTS) were discovered in the late 1980s, there have been enormous efforts to make this into applications such as power transmission cables, transformers, motors and generators. However, many obstacles in performance and high manufacturing cost made this difficult. The first generation HTS wires had low critical current density and were expensive to fabricate. The motivation of this research was to make high performance and low cost second generation HTS coated conductor. Electron beam co-evaporation technique was used to deposit YBCO(YBa2Cu3O7-x ) film at a high rate (10nm/s and higher) on single crystals and metal tapes. The oxygen pressure at the stage of depositing Y, Ba, Cu was 5x10 -5 Torr and the process temperature was 810-840C. In-situ Fourier Transform Infrared spectroscopy (FTIR) was used to monitor the optical properties of the YBCO during and after deposition. The deposit transformed to a glassy amorphous mixture of Y, Ba and Cu at 3 mTorr of oxygen. YBCO crystallization occurred after extra oxygen was applied to several Torr. FTIR showed almost the same signature during the formation of YBCO and liquid Ba-Cu-O during deposition, which indicates the liquid played an important role in determining the properties of YBCO in terms of providing epitaxy and fast transport of atoms to nucleate on the film-metal interface. The transformation was very rapid---seconds to minutes, compared to minutes to hours for other post-reaction processes. The oxygen partial pressure and the rate of oxidation (supersaturation) in the liquid region defined in the YBCO phase stability diagram determined the electrical and microstructural properties. In-situ X-ray diffraction heating stage with ambient control was utilized to study this supersaturation effect and explore the temperature-pressure space during YBCO growth. With all the information gathered from FTIR and XRD in-situ experiments and also with nano-engineering during deposition, the growth process was optimized in the evaporator. As a result, one micron thick YBCO with critical current density of 1.1 MA/cm2 was successfully grown on metal tape. TEM analysis showed a growth mode and microstructure suggestive of lateral growth.

Huh, Jeong-Uk

51

Intermediate State of Thin Superconductors.  

National Technical Information Service (NTIS)

The purpose of the study was to examine the state of a thin type-I superconductor in a magnetic field to determine its dependence on the speciment thickness and on the value of the Ginzburg-Landau parameter k. Three materials (aluminum, indium, and In(0.9...

B. L. Brandt R. D. Parks R. D. Chaudhari

1970-01-01

52

Thin films  

SciTech Connect

This volume is a compilation of papers presented at the 1990 Spring Meeting of the Materials Research Society in a symposium entitled Thin Films: Stresses and Mechanical Properties II. As indicated by the title, the symposium was the second in a series, the first of which was held at the Fall Meeting in 1988. The importance of thin film mechanical properties is now recognized to the extent that basic characterization techniques such as microindentation and thin film stress measurement are performed routinely, and new characterization techniques are being developed on a daily basis. Many of the papers in the symposium dealt with the developments in these characterization methods and their application to a broad spectrum of materials such as compositionally modulated structures, ion implanted materials, optical coatings, and the numerous metals, ceramics and organics used in semiconductor device manufacture.

Doermer, M.F. (International Business Machines Corp., San Jose, CA (United States)); Oliver, W.C. (Oak Ridge National Lab., TN (United States)); Pharr, G.M.; Brotzen, F.R. (Rice Univ., Houston, TX (United States))

1990-01-01

53

Selective laser pyrolysis of metallo-organics as a method of forming patterned thin film superconductors  

SciTech Connect

This patent describes a method for forming patterned films of superconductive materials forming a solution from the neodecanoates of yttrium, barium and copper. The neodecanoates forming an oxide mixture exhibiting superconductive properties upon subsequent thermal decompositions wherein the oxide mixture is characterized by a ratio of yttrium:barium:copper of approximately 1:2:4, the solution comprising an organic solvent such as xylene; adding to the solution an appropriate dye, depositing a film of the solution having the dye onto a strontium titanate substrate; exposing selective regions of the film with an Argon laser emitting the wavelength of light, such that the exposed regions of the film become insoluble in the xylene; immersing the film into the xylene so that the soluble; unexposed regions of the film are removed from the substrate; heating the film to thermally decompose the neodecanoates into a film containing yttrium, barium and copper oxides; to promote recrystallization and grain growth of the metal oxides within the film and induce a change therein by which the film exhibits superconducting properties.

Mantese, J.V.; Catalan, A.B.; Sell, J.A.; Meyer, M.S.; Mance, A.M.

1990-04-10

54

Magnetization curves for thin films of layered type-II superconductors, Kolmogorov-Arnold-Moser theory, and the devil's staircase  

SciTech Connect

Magnetization curves for a thin-layered superconducting film in parallel magnetic field have been shown to become devil's staircases provided the superconducting layers are perpendicular to the film plane. The transition from an incomplete to a complete devil's staircase with decreasing temperature is predicted. A chain of vortices is described by the generalized Frenkel-Kontorova model.

Burkov, S.E. (Laboratory of Atomic and Solid State Physics, Clark Hall, Cornell University, Ithaca, New York (USA) Landau Institute for Theoretical Physics, Moscow (U.S.S.R))

1991-08-01

55

Influence of deposition conditions and ion irradiation on thin films of amorphous Cu?Zr superconductors  

Microsoft Academic Search

Amorphous films of Cu?Zr have been prepared by electron-beam (e-beam) codeposition and ion beam mixing. Various treatments, such as deposition onto liquid nitrogen cooled substrates and ion irradiation with 1 MeV Xe2+ ions or 500 keV Ar+ ions at 100 K and at 300 K, were used to vary the level of disorder in the amorphous state. The residual resistance

N. Karpe; J. Bttiger; J. P. Krog; A. Nordstrm; . Rapp

1996-01-01

56

Preparation of thin film YBa2Cu3O(6+x) ceramic superconductors by the sol-gel process  

NASA Astrophysics Data System (ADS)

High-Tc superconducting powders and thin films on Si have been fabricated by the sol-gel process. Both powder and film preparation involved the synthesis of metal alkoxides, followed by the complexation of Y, Ba, and Cu alkoxides in a common solvent. Bulk gels were then vacuum dried and fired at 700 and 950 C in flowing oxygen. Thin films on (100) Si were fired at 700 C in flowing oxygen. Susceptibility vs temperature measurements showed that the thin films on Si had a Tc of 40 K, while the bulk gels fired under the same conditions had a Tc of 75 K. The sample fired at 950 C was superconducting at 90 K.

Kramer, S.; Wu, K.; Kordas, G.

57

Techniques for Connecting Superconducting Thin Films  

NASA Technical Reports Server (NTRS)

Several improved techniques for connecting superconducting thin films on substrates have been developed. The techniques afford some versatility for tailoring the electronic and mechanical characteristics of junctions between superconductors in experimental electronic devices. The techniques are particularly useful for making superconducting or alternatively normally conductive junctions (e.g., Josephson junctions) between patterned superconducting thin films in order to exploit electron quantum-tunneling effects. The techniques are applicable to both low-Tc and high-Tc superconductors (where Tc represents the superconducting- transition temperature of a given material), offering different advantages for each. Most low-Tc superconductors are metallic, and heretofore, connections among them have been made by spot welding. Most high-Tc superconductors are nonmetallic and cannot be spot welded. These techniques offer alternatives to spot welding of most low-Tc superconductors and additional solutions to problems of connecting most high-Tc superconductors.

Mester, John; Gwo, Dz-Hung

2006-01-01

58

Materials research, superconductor and thin layer technology  

NASA Astrophysics Data System (ADS)

Materials research into polymer electric conductors, organic and inorganic polymer microspheres for chromatography, electronic gas sensor corrosion protection of historic glass windows, soldering of ceramics and metals, fiber reinforced automobile parts, superconductors, and thin layer technology is summarized.

1987-11-01

59

Reversible laser chemically induced phase transformations in thin-film Ba2YCu3O(x) superconductors  

NASA Astrophysics Data System (ADS)

Phase transformations of a thin film of Ba2YCu3O(x) were induced with a focused laser beam in chemical ambients. The transformations, involving superconductive and nonsuperconductive phases, are achieved rapidly and with a high degree of spatial control. They are fully reversible, and the appropriate processing parameters have been studied. These effects are interpreted within present models, which relate the superconducting properties of Ba2YCu3O(x) to its oxygen content and crystalline structure.

Rothschild, M.; Sedlacek, J. H. C.; Black, J. G.; Ehrlich, D. J.

1988-02-01

60

Generic Fe buffer layers for Fe-based superconductors: Epitaxial FeSe1-xTex thin films  

NASA Astrophysics Data System (ADS)

Biaxially textured FeSe1-xTex films have been realized on Fe-buffered MgO substrates by pulsed laser deposition. Similar to the Fe/BaFe2As2 bilayers, the crystalline quality of FeSe1-xTex films exhibit a sharp out-of-plane and in-plane texture less than 0.9. The Fe/FeSe1-xTex bilayers showed high superconducting transition temperatures of over 17 K. The angular-dependent critical current densities exhibit peaks positioned at H ? c similar to other pnictide thin films. The volume pinning force of FeSe1-xTex in this direction is very strong compared with that of Co-doped BaFe2As2, due to a good matching between the interlayer distance in the c direction and the out-of-plane coherence length.

Iida, Kazumasa; Hnisch, Jens; Schulze, Michael; Aswartham, Saicharan; Wurmehl, Sabine; Bchner, Bernd; Schultz, Ludwig; Holzapfel, Bernhard

2011-11-01

61

Role of twins in peak effect phenomenon observed at microwave frequencies in high Tc superconductor thin films  

NASA Astrophysics Data System (ADS)

Measurements of microwave surface resistance, Rs, at subcritical currents as a function of temperature with varying dc magnetic field upto 0.8 T have shown peak effect (PE) in epitaxial DyBa 2Cu 3O 7- ? (DBCO) and YBa 2Cu 3O 7- ? (YBCO) thin films grown by pulsed laser deposition on <1 0 0> LaAlO 3 substrates. Microwave measurements were performed on microstrip resonators as test vehicles. Occurrence of a peak in Rs in dc magnetic field is governed by the nature and concentration of defects. Evidence shows that thinner films with a higher ratio of areal density of extended defects, ne (such as twin boundaries), to the areal density of point defects, np, show PE at the measurement frequencies 4.88 and 9.55 GHz; whereas, thicker films (?3000 ) with a smaller ne/ np ratio do not show PE. 2500 thick YBCO film shows a double peak structure at 9.55 GHz, thereby suggesting two sets of twin boundaries in this film having different ?p values. Measurements carried out on low-twinned LaAlO 3 substrates show that 2400 thick DBCO film does not exhibit the PE phenomenon at 4.88 GHz upto to an applied field of 0.8 T; this indicates that twins propagated from the LaAlO 3 substrates are responsible for the occurrence of PE at microwave frequencies. Oxygen ion irradiation (90 MeV, 3 10 13 ions/cm 2) of 2500 DBCO film has been found to shift the peak to lower temperature at 4.88 GHz, but significantly suppress the peak at 9.55 GHz. Depinning frequency, ?p vs. T plot obtained for the 2400 DBCO film shows a peak due to the peak in its Rs vs. T plots.

Banerjee, Tamalika; Bagwe, V. C.; John, J.; Pai, S. P.; Ganesh Kumara, K.; Pinto, R.

2004-05-01

62

Thin Film Interference Model  

NSDL National Science Digital Library

The Thin Film Interference model investigates reflection and transmission of light through a thin film. The user can change the thickness and index of refraction of the thin film as well as the incident light wavelength. The Thin Film Interference Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_ThinFilm.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

63

Electron-doped superconductor La2-xCexCuO4: Preparation of thin films and modified doping range for superconductivity  

NASA Astrophysics Data System (ADS)

We have investigated transport properties and a related electronic phase diagram of electron-doped La2-xCexCuO4 (LCCO) thin films prepared by pulsed laser deposition. Using BaTiO3 as a buffer layer, we could successfully extend the lower Ce composition limit for synthesis of a single-phase LCCO film down to x=0.06. Superconductivity in LCCO was found to occur within a Ce composition range 0.08<=x<=0.15. The superconducting composition range is apparently shifted toward the lower Ce doping side, as compared with other electron-doped cuprate superconductors, such as Nd2-xCexCuO4 (NCCO). In accord with this, the variations of the resistivity and the Hall effect as a function of Ce content x, are much larger than those of NCCO, tracking the shift of superconducting phase. Indeed, the transport properties of the LCCO films with the shifted optimum composition x=0.11 was found to be equivalent to those of the optimum NCCO (x=0.15). We discuss that this unusual phase diagram of LCCO originates from the reduction of the antiferromagnetic interaction as well as of the electron correlation strength.

Sawa, A.; Kawasaki, M.; Takagi, H.; Tokura, Y.

2002-07-01

64

Pyrolyzed thin film carbon  

NASA Technical Reports Server (NTRS)

A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

2010-01-01

65

An IBA and Raman study of irradiated thin films of YBa 2Cu 3O 7 superconductor  

Microsoft Academic Search

The effect of ion-beam irradiation of YBa2Cu3O7 superconductors has been investigated by Raman spectroscopy. Different ion beams have been used (H, 4He, 12C, 16O and 127I at 1, 4, 10, 25 and 200 MeV, respectively) in an attempt to study the radiation damage with respect to the mass of the bombarding ions. In addition different doses of irradiation have been

R. Vlastou; E. N. Gazis; C. T. Papadopoulos; E. Liarokapis; D. Palles; S. Kossionides; M. Kokkoris; M. Pilakouta; W. Assmann

1996-01-01

66

Films of Iron-Chalcogenide Superconductors and Applications  

NASA Astrophysics Data System (ADS)

Iron chalcogenides are of great interest for both basic physics and applications. Although their superconducting transition temperatures are typically lower than those of iron pnictides, iron chalcogenides exhibit lower anisotropies with very high upper critical field slopes near the superconducting transition temperatures. In this presentation, I will discuss recent progress in the superconducting thin films and coated conductors of iron chalcogenides. The very high upper critical fields and critical current densities of these films suggest that they are prospective candidates for high field and energy applications. - Reference: Qiang Li, Weidong Si, and Ivo Dimitrov, ``Films of Iron-Chalcogenide Superconductors,'' Rep. Prog. Phys. 74 124510 (2011)

Li, Qiang; Si, Weidong

2013-03-01

67

Investigation into the growth and structure of thin-film solid solutions of iron-based superconductors in the FeSe{sub 0.92}-FeSe{sub 0.5}Te{sub 0.5} system  

SciTech Connect

Thin films of FeSe{sub 0.92} and FeSe{sub 0.5}Te{sub 0.5} iron chalcogenide superconductors and solid solutions containing these components in different ratios have been grown on the surface of LaAlO{sub 3} (10 1-bar 2) crystals by pulsed laser deposition. Films of solid solutions have been deposited by simultaneous laser ablation from two targets of the FeSe{sub 0.92} and FeSe{sub 0.5}Te{sub 0.5} stoichiometric compositions onto one substrate. An X-ray diffraction study of the film structure shows that the films grown are epitaxial and their lattice parameters regularly vary with the ratio of the deposited components, which was controllably varied by changing the ablation intensities from the targets.

Stepantsov, E. A., E-mail: stepantsov@ns.cryst.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Kazakov, S. M.; Belikov, V. V. [Moscow State University (Russian Federation)] [Moscow State University (Russian Federation); Makarova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Arpaia, R.; Gunnarsson, R.; Lombardi, F. [Chalmers University of Technology, Department of Microtechnology and Nanoscience (Sweden)] [Chalmers University of Technology, Department of Microtechnology and Nanoscience (Sweden)

2013-09-15

68

Investigation into the growth and structure of thin-film solid solutions of iron-based superconductors in the FeSe0.92-FeSe0.5Te0.5 system  

NASA Astrophysics Data System (ADS)

Thin films of FeSe0.92 and FeSe0.5Te0.5 iron chalcogenide superconductors and solid solutions containing these components in different ratios have been grown on the surface of LaAlO3 (102) crystals by pulsed laser deposition. Films of solid solutions have been deposited by simultaneous laser ablation from two targets of the FeSe0.92 and FeSe0.5Te0.5 stoichiometric compositions onto one substrate. An X-ray diffraction study of the film structure shows that the films grown are epitaxial and their lattice parameters regularly vary with the ratio of the deposited components, which was controllably varied by changing the ablation intensities from the targets.

Stepantsov, E. A.; Kazakov, S. M.; Belikov, V. V.; Makarova, I. P.; Arpaia, R.; Gunnarsson, R.; Lombardi, F.

2013-09-01

69

Quasiparticle generation efficiency in superconducting thin films  

NASA Astrophysics Data System (ADS)

Thin-film superconductors with thickness ?30500 nm are used as non-equilibrium quantum detectors for photons, phonons or more exotic particles. One of the most basic questions in determining their limiting sensitivity is the efficiency with which the quanta of interest couple to the detected quasiparticles. As low temperature superconducting resonators, thin films are attractive candidates for producing quantum-sensitive arrayable sensors and the readout uses an additional microwave probe. We have calculated the quasiparticle generation efficiency ?s for low energy photons in a representative, clean thin-film superconductor (Al) operating well below its superconducting transition temperature as a function of film thickness, within the framework of the coupled kinetic equations described by Chang and Scalapino (1978 J. Low Temp. Phys. 31 132). We have also included the effect of a lower frequency probe. We show that phonon loss from the thin film reduces ?s by as much as 40% compared to earlier models that considered relatively thick films or infinite volumes. We also show that the presence of the probe and signal enhances the generation efficiency slightly. We conclude that the ultimate limiting noise equivalent power of this class of detector is determined by the thin-film geometry.

Guruswamy, T.; Goldie, D. J.; Withington, S.

2014-05-01

70

Metal organic chemical vapor deposition of superconducting YBa2Cu3O7-x thin films  

Microsoft Academic Search

The discovery of YBCO superconductors has stimulated a great deal of scientific and technological research into thin films of these materials. Because the MOCVD technique is known to produce high quality films in the III\\/V and II\\/VI material groups, our approach has been to apply the method to superconducting thin films. Thin films were grown in a vertical high speed

P. A. Zawadzki; G. S. Tompa; P. E. Norris; C. S. Chern; R. Caracciolo; B. H. Kear; D. W. Noh; B. Gallois

1990-01-01

71

Superconducting thin films of YBa2Cu3O(7-x).  

National Technical Information Service (NTIS)

Thin films of YBa2Cu3O(7-x) (YBCO) are significant in fundamental studies of oxide superconductors and for prospective electronic applications based on superconductors operating at 77 K. Synthesis of YBCO thin films is complex and a large part of this the...

J. Hudner

1993-01-01

72

Thin-film metal coated insulation barrier in a Josephson tunnel junction. [Patent application  

Microsoft Academic Search

A highly stable, durable, and reproducible Josephson tunnel junction consists of a thin-film electrode of a hard superconductor, a thin oxide insulation layer over the electrode constituting a Josephson tunnel junction barrier, a thin-film layer of stabilizing metal over the barrier, and a second thin-film hard superconductive electrode over the stabilizing film. The thin stabilizing metal film is made only

G. A. Hawkins; J. Clarke

1975-01-01

73

Thin-film optical initiator  

Microsoft Academic Search

A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin

Kenneth L

2001-01-01

74

Atomically-flat, chemically-stable, superconducting epitaxial thin film of iron-based superconductor, cobalt-doped BaFeAs  

NASA Astrophysics Data System (ADS)

The epitaxial growth of Fe-based superconductors such as Co-doped SrFe 2As 2 (SrFe 2As 2:Co) was reported recently, but has still insufficient properties for a device application because they have rough surfaces and are decomposed by reactions with water vapor in an ambient atmosphere. This paper reports that epitaxial films of Co-doped BaFe 2As 2 grown at 700 ?C show the onset superconducting transition temperature of 20 K. The transition is sharper than those observed on the SrFe 2As 2:Co films, which would originate from their improved crystallinity. These films also have atomically-flat surfaces with step-and-terrace structures and exhibit chemical stability against exposure to water vapor.

Katase, Takayoshi; Hiramatsu, Hidenori; Yanagi, Hiroshi; Kamiya, Toshio; Hirano, Masahiro; Hosono, Hideo

2009-12-01

75

Thin-film photovoltaics  

Microsoft Academic Search

CdTe and CuIn1-xGaxSe2-ySy (CIGSS) are ideal candidates for thin-film solar cells. Present photovoltaic (PV) conversion efficiencies of champion thin-film solar cells are: CuIn1-xGaxSe2 (CIGS) 19.5%, CdTe 16.5%, and a-Si:H 12.4%. Thin-film PV modules could spearhead production growth of photovoltaics in the United States because of their added production capacity. For this purpose, module efficiencies must be improved to the 13%-15%

Neelkanth G. Dhere; Ramesh G. Dhere

2005-01-01

76

Thin Film Growth  

NSDL National Science Digital Library

This is a PDF version of lecture slides that discuss thin film growth processes. Slide topics include plasma properties, DC glow discharge, ionization, plasma species, magnetrons, collisions, and chemical reactions. Numerous charts and mathematical formulas are presented.

Rack, Philip D.

2010-07-19

77

Exploring Materials: Thin Films  

NSDL National Science Digital Library

In this activity, learners create a colorful bookmark using a super thin layer of nail polish on water. Learners discover that a thin film creates iridescent, rainbow colors. This is a very fun and engaging activity for learners, and a great way to talk about how nanoscale structures often affect a materials' properties. SAFETY: Do this activity in a well-ventilated area.

Network, Nanoscale I.; Sciencenter

2010-01-01

78

Thin Film Colorimetric Interferometry  

Microsoft Academic Search

Measurement technique for the study of very thin lubrication films down to one nanometer in a point contact between a steel ball and a transparent disc is used to explore the relationship between central and minimum film thickness and rolling speed at the interface between elastohydrodynamic and boundary lubrication for a series of lubricating fluids. This technique based on the

M. Hartl; I. Krupka; R. Poliscuk; M. Liska; J. Molimard; M. Querry; P. Vergne

2001-01-01

79

Paramagnetic Response in Thin Films of Electron-Doped Superconductor Pr_2-xCe_xCuO_4-y at Various Doping Levels  

NASA Astrophysics Data System (ADS)

Strong paramagnetic effect was observed in a superconducting state of optimally doped and overdoped Pr_2-xCe_xCuO_4-y (PCCO) thin films by using DC magnetometer. Underdoped films did not exhibit this anomaly. Radio-frequency measurements of the penetration depth in the same films did not reveal paramagnetic response implying DC nature of the observed effect. The relevance of our results to the appearance of spontaneous currents resulting from the Andreev bound states, to the conventional Wohlleben effect as well as to the similar observations in hole-doped materials are discussed.

Prozorov, Ruslan; Snezhko, Alexey; Fournier, Patrick

2003-03-01

80

Heterogeneity in Polymer Thin Films  

NASA Astrophysics Data System (ADS)

In the last two decades very extensive studies have been performed on polymer thin films to reveal very interesting but unusual properties. One of the most interesting findings is the decrease in glass transition temperature Tg with film thickness in polystyrene (PS) thin film supported on Si substrate. Another interesting finding is apparent negative thermal expansivity in glassy state for thin films below ~25 nm. In order to understand the unusual properties of polymer thin films we have studied temperature dependence of thickness of polystyrene thin films by means of X-ray and neutron reflectivity. In addition, we also studied dynamics of PS thin films using inelastic neutron scattering. In the presentation we will discuss the results from viewpoints of heterogeneity of polymer thin films. Finally we did neutron reflectivity measurements on a 5-layer thin film, consisting of alternatively stacked d-PS and h-PS layers to see the distribution of glass transition temperature and thermal expansivity directly.

Kanaya, Toshiji; Inoue, Rintaro; Nishida, Koji

2011-07-01

81

Thin film photovoltaics  

SciTech Connect

Thin films are considered a potentially attractive technological approach to making cost-effective electricity by photovoltaics. Over the last twenty years, many have been investigated and some (cadmium telluride, copper indium diselenide, amorphous silicon) have become leading candidates for future large-scale commercialization. This paper surveys the past development of these key thin films and gives their status and future prospects. In all cases, significant progress toward cost-effective PV electricity has been made. If this progress continues, it appears that thin film PV could provide electricity that is competitive for summer daytime peaking power requirements by the middle of the 1990s; and electricity in a range that is competitive with fossil fuel costs (i.e., 6 cents/kilowatt-hour) should be available from PV around the turn of the century. 22 refs., 9 figs.

Zweibel, K.; Ullal, H.S.

1989-05-01

82

Thin film temperature sensor  

NASA Technical Reports Server (NTRS)

Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

Grant, H. P.; Przybyszewski, J. S.

1980-01-01

83

Intermodulation distortion in HTS thin films: a global heating model  

NASA Astrophysics Data System (ADS)

The non-linear microwave response of high transition-temperature superconductors (HTS) thin films is a critical issue for applications of the cuprates in future communications technologies. We report that the conventional figure of merit, the third-order intercept, does not provide a good measure of performance for HTS materials. We describe a physical model for intermodulation distortion generation which arises from global heating effects in a thin film, not previously noted. We present results on a high quality YBCO thin film which support the validity of this model. Predictions are made of techniques to reduce the intermodulation in films of this quality.

Hao, Ling; Gallop, John; Purnell, Adrian; Cohen, Lesley

2002-08-01

84

Thin film ceramic thermocouples  

NASA Technical Reports Server (NTRS)

A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

2011-01-01

85

Thin film photovoltaic device  

DOEpatents

A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

Catalano, Anthony W. (Wilmington, DE); Bhushan, Manjul (Wilmington, DE)

1982-01-01

86

Thin film photovoltaic device  

DOEpatents

A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

Catalano, A.W.; Bhushan, M.

1982-08-03

87

Thin-film optical initiator  

SciTech Connect

A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

Erickson, Kenneth L. (Albuquerque, NM)

2001-01-01

88

NMR characterization of thin films  

DOEpatents

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

Gerald, II, Rex E. (Brookfield, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Homer Glen, IL); Diaz, Rocio (Chicago, IL); Vukovic, Lela (Westchester, IL)

2008-11-25

89

Preparations of magnetoelectric thin films for superconducting devices  

Microsoft Academic Search

Representative magnetoelectric (ME) Cr2O3 thin films were grown on R-cut sapphire and SrTiO3(100) substrate in order to integrate with high temperature superconductor oxides. The replacement of a base current and stabilization of IC spread for single flux quantum device is expected. Highly oriented Cr2O3 thin film grew on sapphire at 550C by off-axis DCRF hybrid magnetron sputtering method with two-in.

N. Iwata; T. Asada; K. Nagase; T. Yamada; H. Yamamoto

2007-01-01

90

The effect of process gas pressure, target composition, Ar:O2 ratio and substrate bias on the preparation of thin films of the superconductor Bi2Sr2CaCu2O8+?  

NASA Astrophysics Data System (ADS)

Thin films prepared by DC magnetron sputtering of single targets of the well known superconductor Bi2Sr2CaCu2O8+? and an enriched target of composition Bi2.2Sr2Ca1.1Cu2O8+? were studied to determine the effect of deposition conditions on the resulting film. The targets were both sputtered at a power of 60 Watts for 83.3 minutes, at a base pressure of (51)x10-7 Torr. Films were deposited onto Al foil using a comprehensive range of deposition pressures (3.96 to 27.3 mTorr), Ar:O2 gas ratios (1:1, 1:2, 1:3 and 2:1) and substrate biases (-5, -20, and -30 V). Elemental analysis using energy dispersive spectroscopy allows us to determine the effect of these variables on each individual element in the deposited film. The proportion of Bi increases linearly with increasing process gas pressure. Changing the Ar:O2 ratio does not have a major effect on the composition, but it does slightly vary the Sr and Ca concentrations. Resputtering was present in the film which had a -5 V bias, the -30 V bias also showed a reduced elemental composition, while the -20 V bias produced the best composition. The results of this study show the fickle nature of depositing films from multi-element oxide targets, and the need to optimize conditions to produce the desired film.

Sanderson, Robert J.; Hewitt, Kevin C.

2006-03-01

91

Thin Film Microstrip Circuits.  

National Technical Information Service (NTIS)

A four layer thin film metallization system is comprised of layers of tantalum, chromium, copper and gold and is useful in high resolution, low loss microstrip circuits. The metallization system is compatible with lead-tin solder and, in addition, provide...

R. D. Hall

1982-01-01

92

Tunable Coplanar Waveguide Microwave Devices on MOCVD-SrTiO3 Thin Films  

Microsoft Academic Search

SrTiO3 (STO) ferroelectric (FE) thin films associated with high temperature superconductors (HTSC) make a good compromise to realize electronically tunable microwave devices combining controllable dielectric properties of FE films with low loss microwave conductivity in HTSC. Up to now, STO thin films dedicated to this function were deposited by sputtering and pulsed laser deposition. In this study, we have explored

A. Gensbittel; A. F. Dgardin; F. Weiss; A. J. Kreisler

2008-01-01

93

Formation of film superconductors by metallo-organic deposition  

SciTech Connect

This patent describes a method for producing thin film superconductor materials. It comprises forming a solution from the neodecanoates of yttrium, barium, and copper metals; depositing a film of the solution onto a substrate. The substrate selected from the group consisting of strontium titanate, barium titanate, and sapphire; pyrolyzing the film in an oxygen-containing environment at a first temperature of about 500{degrees}C. for about 5 minutes, so as to decompose the neodecanoates of yttrium, barium, and copper into a film containing oxides of yttrium, barium, and copper, the pyrolyzing occurring substantially immediately after the depositing step; and heating the metal oxide film to a second temperature of about 850{degrees}C. for a duration of approximately no more than 2 minutes and allowing the metal oxide film to cool to room temperature, then heating the metal oxide film to a third temperature of about 920{degrees}C. for a duration of approximately no more than 1 minute.

Micheli, A.L.; Dungan, D.F.; Hamdi, A.H.; Mantese, J.V.; Laugal, R.C.O.

1990-10-09

94

Basic Research on the Correlation of Superconducting Properties with Surface Properties in Both Thin Film and Bulk Superconducting.  

National Technical Information Service (NTIS)

This report details the accomplishments of a study of the correlation of surface properties and superconducting properties of thin film superconductors. This report may be conveniently divided into three broad areas, (1) surface characterization, (2) thin...

C. R. Haden J. H. Peavey R. C. Jerner

1975-01-01

95

Metal organic chemical vapor deposition of superconducting YBa 2 Cu 3 O 7-x thin films  

Microsoft Academic Search

The discovery of YBCO superconductors has stimulated a great deal of scientific and technological research into thin films\\u000a of these materials. Because the MOCVD technique is known to produce high quality films in the III\\/V and II\\/VI material groups,\\u000a our approach has been to apply the method to superconducting thin films. Thin films were grown in a vertical high speed

P. A. Zawadzki; G. S. Tompa; P. E. Norris; C. S. Chern; R. Caracciolo; B. H. Kear; D. W. Noh; B. Gallois

1990-01-01

96

Advanced thin film thermocouples  

NASA Technical Reports Server (NTRS)

The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

Kreider, K. G.; Semancik, S.; Olson, C.

1984-01-01

97

Thin film resonator technology.  

PubMed

Advances in wireless systems have placed increased demands on high performance frequency control devices for operation into the microwave range. With spectrum crowding, high bandwidth requirements, miniaturization, and low cost requirements as a background, the thin film resonator technology has evolved into the mainstream of applications. This technology has been under development for over 40 years in one form or another, but it required significant advances in integrated circuit processing to reach microwave frequencies and practical manufacturing for high-volume applications. This paper will survey the development of the thin film resonator technology and describe the core elements that give rise to resonators and filters for today's high performance wireless applications. PMID:16048174

Lakin, Kenneth M

2005-05-01

98

Thin Film Multilayer Conductor/Ferroelectric Tunable Microwave Components for Communication Applications.  

National Technical Information Service (NTIS)

High Temperature Superconductor/Ferroelectric (HTS/FE ) thin film multilayered structures deposited onto dielectric substrates are currently being investigated for use in low loss, tunable microwave components for satellite and ground based communications...

F. A. Miranda R. R. Romanofsky F. W. VanKeuls C. H. Mueller R. E. Treece T. V. Rivkin

1997-01-01

99

Dewetting of Thin Polymer Films  

NASA Astrophysics Data System (ADS)

DEWETTING OF THIN POLYMER FILMS P. S. Dixit,(1) J. L. Sorensen,(2) M. Kent,(2) H. S. Jeon*(1) (1) Department of Petroleum and Chemical Engineering, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, jeon@nmt.edu (2) Department 1832, Sandia National Laboratories, Albuquerque, NM. Dewetting of thin polymer films is of technological importance for a variety of applications such as protective coatings, dielectric layers, and adhesives. Stable and smooth films are required for the above applications. Above the glass transition temperature (Tg) the instability of polymer thin films on a nonwettable substrate can be occurred. The dewetting mechanism and structure of polypropylene (Tg = -20 ^circC) and polystyrene (Tg = 100 ^circC) thin films is investigated as a function of film thickness (25 h < 250 and quenching temperature. Contact angle measurements are used in conjunction with optical microscope to check the surface homogeneity of the films. Uniform thin films are prepared by spin casting the polymer solutions onto silicon substrates with different contact angles. We found that the stable and unstable regions of the thin films as a function of the film thickness and quenching temperature, and then constructed a stability diagram for the dewetting of thin polymer films. We also found that the dewetting patterns of the thin films are affected substantially by the changes of film thickness and quenching temperature.

Dixit, P. S.; Sorensen, J. L.; Kent, M.; Jeon, H. S.

2001-03-01

100

Thin film composite electrolyte  

DOEpatents

The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

Schucker, Robert C. (The Woodlands, TX)

2007-08-14

101

Thin film mechanics  

NASA Astrophysics Data System (ADS)

This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate the role of grain boundaries on the strength of chemical vapor deposited graphene. The results from these studies suggest that two dimensional films have remarkably high strength-reaching the intrinsic limit of molecular bonds. Chapter 5 explores the viscoelastic properties of heterogeneous polydimethylsiloxane (PDMS) microfilms through dynamic nanoindentation. PDMS microfilms are irradiated with an electron beam creating a 3 m-thick film with an increased cross-link density. The change in mechanical properties of PDMS due to thermal history and accelerator have been explored by a variety of tests, but the effect of electron beam irradiation is still unknown. The resulting structure is a stiff microfilm embedded in a soft rubber with some transformational strain induced by the cross-linking volume changes. Chapter 5 employs a combination of dynamic nanoindentation and finite element analysis to determine the change in stiffness as a function of electron beam irradiation. The experimental results are compared to the literature. The results of these experimental and numerical techniques provide exciting opportu- nities in future research. Two dimensional materials and flexible thin films are exciting materials for novel applications with new form factors, such as flexible electronics and microfluidic devices. The results herein indicate that you can accurately model the strength of two dimsensional materials and that these materials are robust against nanoscale defects. The results also reveal local variation of mechanical properties in PDMS microfilms. This allows one to design substrates that flex with varying amounts of strain on the surface. Combining the mechanics of two dimensional materials with that of a locally irradiated PDMS film could achieve a new class of flexible microelectromechanical systems. Large-scale growth of two dimensional materials will be structurally robust-even in the presence of nanostructural defects-and PDMS microfilms can be irradiated to vary strain of the electromechanical systems. These systems could be designed to investigate e

Cooper, Ryan C.

102

New buffer materials for high T c superconducting thin films  

NASA Astrophysics Data System (ADS)

We have tested La2O3, Gd2O3, Y2O3, Dy2O3, and PrO1.82 as new buffer materials for high T c superconducting thin films. These oxides are structurally compatible with the superconductors. The cubic phase of La2O3 cannot be stabilized and Nd2O3 films have mixed cubic and hexagonal phases in the temperature and pressure ranges used in the experiment. All other oxides are suitable and also chemically compatible with YBa2Cu3O7-? superconductor. YBa2Cu3O7-? thin films on these buffer materials have a superconducting transition temperature of 90 K. (100) oriented films of these oxides were not obtained on R-plane sapphire without a CeO2 seed layer.

Wu, X. D.; Luo, L.; Muenchausen, R.; Foltyn, S. R.; Dye, R. C.; Nogar, N. S.

1992-05-01

103

Development of Preparation of the Functional Thin Films by Pulsed Laser Deposition  

Microsoft Academic Search

Pulsed laser deposition (PLD) exhibits unique advantages for the preparation of functional thin films which are widely used in microelectronics, photoelectrons, integrate circuits, superconductors and biomedical fields. The principle of and the characteristics of PLD are introduced, its applications in ferroelectrics, high-temperature superconductors, diamond-like and superlattices. The future application trend is reviewed.

Yafan Zhao; Chuanzhong Chen; Lubin Chen; Quanhe Bao

2005-01-01

104

Thin film hydrogen sensor  

DOEpatents

A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

Lauf, Robert J. (Oak Ridge, TN) [Oak Ridge, TN; Hoffheins, Barbara S. (Knoxville, TN) [Knoxville, TN; Fleming, Pamela H. (Oak Ridge, TN) [Oak Ridge, TN

1994-01-01

105

Nonlinear optical thin films  

NASA Technical Reports Server (NTRS)

A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film-forming material in a working device is a complex, multifaceted endeavor. It requires close attention to maintaining the optical properties of the electro-optic active portion of the polymer while manipulating the polymer structure to obtain the desired secondary polymer properties.

Leslie, Thomas M.

1993-01-01

106

Thin Film Inorganic Electrochemical Systems.  

National Technical Information Service (NTIS)

During the 21 month period of this contract we have studied components for an all inorganic thin film lithium ion cell. During this work we have determined that thin film cathodes of LiCoO2 can be readily performed by either spray pyrolysis or spin coatin...

D. M. Schleich

1995-01-01

107

Thin film atomic hydrogen detectors  

NASA Technical Reports Server (NTRS)

Thin film and bead thermistor atomic surface recombination hydrogen detectors were investigated both experimentally and theoretically. Devices were constructed on a thin Mylar film substrate. Using suitable Wheatstone bridge techniques sensitivities of 80 microvolts/2x10 to the 13th power atoms/sec are attainable with response time constants on the order of 5 seconds.

Gruber, C. L.

1977-01-01

108

Effect of ion irradiation induced defects on the excess conductivity of Cu 1-xTl xBa 2Ca 1Cu 2O 8-? superconductor thin films  

NASA Astrophysics Data System (ADS)

The Cu 1-xTl xBa 2Ca 1Cu 2O 8-? superconductor thin film samples were bombarded with protons, Si and Au ions of energies 6, 20 and 20 MeV respectively using 5MV tandem pelletron accelerator at Experimental Physics Labs. Each un-irradiated sample had different values of normal state resistivity and the zero resistance critical temperature. The zero resistivity critical temperature has been increased after the irradiation by Si and Au ions. The fluctuation induced conductivity (FIC) analysis of the as-prepared and the ion irradiated samples were performed in the light of Aslamasov-Larkin (AL) theory. The FIC analysis has shown three dimensional (3D) fluctuations in the order parameter in all the samples along with a cross-over to two dimensional (2D) fluctuations at higher temperature. The 3D-2D cross-over temperature has been shifted to higher values after the ion irradiation. Moreover, a direct correlation between the zero resistivity critical temperature, 2D-3D cross-over temperature ( TLD) and superconductivity fluctuation temperature ( Tscf) was observed. These studies have shown that the fluctuation induced conductivity (excess conductivity) depends on the density of defects and is independent of their nature.

Khurram, A. A.; Khan, Nawazish A.; Ahmad, Shakeel; Awais, Ali

2011-01-01

109

Transport properties at the insulator-superconductor phase boundary of La 2- xSr xCuO 4 thin films  

NASA Astrophysics Data System (ADS)

The longitudinal resistivity and the transverse Hall resistivity of La 1.94Sr 0.06CuO 4 and La 1.97Sr 0.03CuO 4 epitaxial thin films are investigated. The zero-field resistivity ?( T) of La 1.94Sr 0.06CuO 4 shows a minimum at 80 K and a resistive midpoint of the superconducting transition at Tcmid?7.5 K. A magnetic field of 8 T suppresses the superconducting state and induces a semiconducting normal state with ?( T) increasing with decreasing temperature. The resistivity of La 1.97Sr 0.03CuO 4 has a minimum at 100 K and no superconducting transition is observed down to 1.5 K. The semiconducting low-temperature behaviour can be described by Shlovskii-Efros hopping, while the metallic-like regime corresponds to 1D quantum transport of charge stripes. The field dependence of the Hall resistivity ? xy( B) has an opposite behaviour for the two doping levels: the ? xy( B) slope of La 1.94Sr 0.06CuO 4 decreases with decreasing temperature, while it increases in the case of La 1.97Sr 0.03CuO 4. Within the superconducting transition regime of La 1.94Sr 0.06CuO 4 (below 15 K) we observe a sign inversion of ? xy( B) in the limit of weak magnetic fields.

Wagner, P.; Ruan, K.-Q.; Gordon, I.; Vanacken, J.; Moshchalkov, V. V.; Bruynseraede, Y.

2001-07-01

110

Commensurate vortex lattices in thin vanadium films and in V\\/Si superconducting superlattices  

Microsoft Academic Search

The features of the Shubnikov phase in thin films of type-II superconductors are investigated in the case when the magnetic field is parallel to the surface of the film. Measurements of the nonmonotonic dependence of the critical current Ic on the magnetic field H∥ reveal commensurate vortex lattices with different numbers of vortex chains in the film. It is proved

N. Ya. Fogel; E. I. Buchstab; V. G. Cherkasova; O. I. Yuzephovich; M. Yu. Mikhailov; A. N. Stetzenko

2001-01-01

111

Fabrication of high-quality superconductor-insulator-superconductor junctions on thin SiN membranes  

NASA Technical Reports Server (NTRS)

We have successfully fabricated high-quality and high-current density superconductor-insulator-superconductor (SIS) junctions on freestanding thin silicon nitride (SIN) membranes. These devices can be used in a novel millimeter-wave and THz receiver system which is made using micromachining. The SIS junctions with planar antennas were fabricated first on a silicon wafer covered with a SiN membrane, the Si wafer underneath was then etched away using an anisotropic KOH etchant. The current-voltage characteristics of the SIS junctions remained unchanged after the whole process, and the junctions and the membrane survived thermal cycling.

Garcia, Edouard; Jacobson, Brian R.; Hu, Qing

1993-01-01

112

Thin film hydrogen sensor  

DOEpatents

A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed. 6 figs.

Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

1994-11-22

113

Planar tunnel junction on oxygen doped iron telluride thin films  

NASA Astrophysics Data System (ADS)

Since its discovery, iron based superconductivity has garnered much interest from the research community for its potential in both application and fundamental science. One of the questions awaiting an answer is the pairing symmetry of this new class of superconductors. Recently, Koshelev and Stanev proposed a fingerprint of s+- symmetry in the NIS tunneling spectrum where the iron based superconductor is proximity-coupled to a thin s-wave superconductor[1]. We have prepared oxygen doped iron telluride (FeTe:Ox) thin films, along with an in-situ grown tunnel barrier and top electrode by Molecular Beam Epitaxy (MBE). We have fabricated them into planar tunnel junction and will report the temperature dependence of both tunneling and point contact spectra. [1]. A. E. Koshelev and V. Stanev, EPL (Europhysics Letters) 96 (2), 27014 (2011).

Zheng, Mao; Zhao, Han; Zhang, Can; Olson, Gustaf; Mulcahy, Brian; Stanev, Valentin; Koshelev, Alexei; Greene, Laura; Eckstein, James

2013-03-01

114

Fabrication, Thickness Dependence of Superconducting Transition, and Temperature and Field Dependences of Critical Current Density in High-Temperature Superconductor Thin Films  

Microsoft Academic Search

Fabrication of YBCO post-annealed and in-situ films is described. The reproducibility of films is obtained after solving several problems. In general, post-anneal films have larger thicknesses and broader transition width. The x-ray diffraction spectra from these samples show preferentially c-orientation with some impurities. However, the in-situ films have thickness around 100 to 200 nm and transition width of 1.5 to

Iatneng Chan

1992-01-01

115

Thin-Film Phase Shifters.  

National Technical Information Service (NTIS)

This work has concentrated on developing thin-film tunable dielectric technology towards commercial viability for phase-shifters. Agile's varactor and phase shifter modeling has demonstrated the potential for this technology to provide low loss phase shif...

C. Elsass

2003-01-01

116

Interference Colors in Thin Films.  

ERIC Educational Resources Information Center

Explains interference colors in thin films as being due to the removal, or considerable reduction, of a certain color by destructive inteference that results in the complementary color being seen. (GA)

Armstrong, H. L.

1979-01-01

117

The thin film microwave iris  

NASA Technical Reports Server (NTRS)

Development of waveguide iris for microwave coupling applications using thin film techniques is discussed. Production process and installation of iris are described. Iris improves power transmission properties of waveguide window.

Ramey, R. L.; Landes, H. S.; Manus, E. A.

1972-01-01

118

Simulation of Thin Film Formation.  

National Technical Information Service (NTIS)

This project aims to develop modeling and simulation tools to describe the chemical and physical processes important to the manufacture of thin films on semiconductor substrates. We have developed software simulation tools that model chemical and physical...

R. B. Walker J. D. Kress D. E. Hanson T. Gammel

2000-01-01

119

Thin Film Accelerated Life Tests.  

National Technical Information Service (NTIS)

The purpose of this program was to study, investigate and develop test and measurement techniques for controllably accelerating the aging processes in tantalum thin film R-C networks, and to investigate the physics of failure associated with the networks....

M. J. Walker M. Sharp

1966-01-01

120

Thin film ferroelectrics: breakthrough  

NASA Astrophysics Data System (ADS)

Now that commercial infrared is a well-established business with several serious competitors, the pressures for a competitive edge have increased dramatically. Hybrid barium strontium titanate (BST) ferroelectric detectors still provide the basis for the majority of systems being produced today, and tens of thousands of systems have been fielded. The system simplicity of these AC-coupled systems is not matchable by any other current technology, but the complexity of the detector fabrication process limits its potential for further substantial cost and performance improvements. DC-coupled VOx bolometers, currently the most popular technology among manufacturers, offer better sensitivity at somewhat greater cost. Although this technology has been heralded as the technology of the future, it is encumbered by a more complicated system architecture and by spatial noise, which limits the ability to take advantage of its greater sensitivity. Thin-film ferroelectric (TFFE) detectors promise to remove the cost and performance barriers that lie ahead of BST technology, while maintaining the low system cost and low spatial noise characteristic of AC-coupled systems. Until recently the promise has been elusive, but now real-world performance of the best of TFFE systems is competitive with the best of any other technology.

Hanson, Charles M.; Beratan, Howard R.

2002-08-01

121

Process for forming epitaxial perovskite thin film layers using halide precursors  

DOEpatents

A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

Clem, Paul G. (Albuquerque, NM); Rodriguez, Mark A. (Albuquerque, NM); Voigt, James A. (Corrales, NM); Ashley, Carol S. (Albuquerque, NM)

2001-01-01

122

Thin film corrosion. Final report  

SciTech Connect

Corrosion of chromium/gold (Cr/Au) thin films during photolithography, prebond etching, and cleaning was evaluated. Vapors of chromium etchant, tantalum nitride etchant, and especially gold etchant were found to corrosively attack chromium/gold films. A palladium metal barrier between the gold and chromium layers was found to reduce the corrosion from gold etchant.

Raut, M.K.

1980-06-01

123

Sectioned thin-film grating  

Microsoft Academic Search

The resolving power of metallic linear gratings deposited on a dielectric thin-film waveguide can be increased by separating sections of the grating by blank spaces. Because of the high coupling efficiencies of gratings deposited directly on the waveguide, the effects of the blank spaces cannot be observed for such guides. If a dielectric film with an index of refraction less

W. D. Westwood; J. W. Y. Lit

1974-01-01

124

Transport Phase Diagram of Homogeneously Disordered Superconducting Thin Films  

Microsoft Academic Search

We have constructed a phase diagram in temperature-magnetic field-disorder space for homogeneously disordered superconducting tantalum thin films. Phases are phenomenologically identified by the nonlinear transport characteristics that are unique in each phase. The resulting phase diagram shows that a direct superconductor-insulator transition is prohibited at any disorder because the superconducting phase is completely surrounded by the intervening metallic phase.

Yize Li; Carlos L. Vicente; Jongsoo Yoon

2009-01-01

125

Vapor deposition of thin films  

DOEpatents

A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

1992-01-01

126

Thin Films for Thermoelectric Applications  

NASA Astrophysics Data System (ADS)

The introduction of nanotechnology opened new horizons previously unattainable by thermoelectric devices. The nano-scale phenomena began to be exploited through techniques of thin-film depositions to increase the efficiency of thermoelectric films. This chapter reviews the fundamentals of the phenomenon of thermoelectricity and its evolution since it was discovered in 1822. This chapter also reviews the thermoelectric devices, the macro to nano devices, describing the most used techniques of physical vapor depositions to deposit thermoelectric thin-films. A custom made deposition chamber for depositing thermoelectric thin films by the thermal co-evaporation technique, where construction issues and specifications are discussed, is then presented. All the steps for obtaining a thermoelectric generator in flexible substrate with the custom deposition chamber (to incorporate in thermoelectric microsystems) are described. The aim of thermoelectric microsystem relays is to introduce an energy harvesting application to power wireless sensor networks (WSN) or biomedical devices. The scanning probe measuring system for characterization of the thermoelectric thin films are also described in this chapter. Finally, a few of the prototypes of thermoelectric thin films (made of bismuth and antimony tellurides, {Bi}2{Te}3, and {Sb}2{Te}3, respectively) obtained by co-evaporation (using the custom made deposition chamber) and characterized for quality assessment are dealt with. All the issues involved in the co-evaporation and characterization are objects of analysis in this chapter.

Silva, M. F.; Ribeiro, J. F.; Carmo, J. P.; Gonalves, L. M.; Correia, J. H.

127

Magnesium diboride thin films and devices  

NASA Astrophysics Data System (ADS)

Magnesium diboride (MgB2) is a binary compound superconductor with a superconducting transition temperature Tc of 40 K. MgB2 has two conduction bands: a two-dimensional sigma band and a three-dimensional pi band with weak interband scattering. The two gap superconductivity in MgB2 gives rise to many interesting physical properties not possible in other superconductors. The relatively high Tc combined with phonon mediated superconductivity and relatively long coherence length makes MgB2 promising for electronics applications like rapid single flux quantum (RSFQ) logics and superconducting quantum interference devices (SQUID). The high current density and record-high upper critical field in pure or alloyed MgB2 are also attractive to a variety of high field applications including cryogen-free Magnetic Resonance Imaging (MRI) systems. MgB2 may also be used in RF cavity coatings due to its low surface resistance and in photo detection due to its fast photoresponse coupled with relatively high Tc. High quality epitaxial thin films are produced by the hybrid physical-chemical vapor deposition (HPCVD) technique. The HPCVD MgB2 thin films have the highest Tc and lowest resistivity with sharp transition of all MgB2 materials reported. The HPCVD MgB2 material is free of dendritic flux jumps due to its low resistivity. The root-mean-square (RMS) surface roughness of HPCVD MgB2 films can be 1 nm when 1% of nitrogen is added to the hydrogen carrier gas during the growth. The stability of MgB2 films in water is studied; it is found that degradation can be prevented by a thin (10 nm) MgO layer deposited on the film surface. The Tc is enhanced by tensile strain due to the Volmer-Weber growth mode and the mismatches between MgB2 and the substrate in the lattice constants and the coefficients of thermal expansion. High quality superconductor-insulator-superconductor Josephson tunnel junctions were made with various barrier formation techniques. The junction critical current densities and IcRn products are high with clear gap characteristics and low subgap currents. The Fraunhofer-pattern of Josephson supercurrent modulation in magnetic fields demonstrates excellent junction uniformity. The barrier thickness and height were estimated, and the barrier composition was studied by X-ray Photoelectron Spectroscopy (XPS). Josephson tunnel junctions with non-c-axis-oriented MgB2 were made which clearly exhibit tunneling spectra from both MgB2 superconducting gaps. The two-band superconductivity and its effect on vortices were studied by tunneling spectroscopy in magnetic fields. Planar all-MgB2 Josephson junctions were made by creating a weak-link through a TiB2 underlayer or an ion damaged MgB 2. Junctions exhibited Josephson critical current and RSJ-like characteristics and Shapiro steps under microwave radiation. Uniform ion damage MgB2 Josephson junction array was also demonstrated.

Cui, Yi

128

High Tc thin film and device development  

NASA Astrophysics Data System (ADS)

Thin films of the high-Tc superconductor YBa2Cu3O(y) have been deposited on various substrates by diode and magnetron sputtering using bulk sintered targets. These films have been analyzed by a variety of methods: scanning electron microscopy, X-rays, electron beam microprobe, mass spectrometry and Raman spectroscopy. The stoichiometries of the films have been measured as a function of the radial position from the center of the sputtered beam at a fixed target-substrate distance. Patterning of the films has been carried out to form planar structures such as strip lines, microbridges and RF SQUIDs (superconducting quantum interference devices). The DC current-voltage characteristics of the microbridges were measured as a function of temperature. RF SQUID behavior has been observed for single-loop devices and their properties established at 4.2 K and higher temperatures. Flux-locked noise spectra with a 1/f noise power response were recorded in the frequency range from 0.01 to about 100 Hz. RF SQUID signals have been observed for temperatures up to 55 K.

Betts, K.; Burbank, M. B.; Cragg, A.; Fife, A. A.; Kubik, P. R.

1989-03-01

129

Light Amplification in a Thin Film.  

National Technical Information Service (NTIS)

Light Amplification at 6328 A in a rhodamine-B-doped polyurethane thin film is observed. The light-guiding thin film is pumped transversely with a nitrogen laser. Superradiant light of the dye-doped film is observed to be guided by the thin film. When a H...

C. Hu J. R. Whinnery M. S. Chang P. Burlamacchi

1972-01-01

130

Type II Film Superconductors for Power Applications.  

National Technical Information Service (NTIS)

A basic theoretical background of type II superconductors and an introduction into materials are presented. The requirements for these materials for Army power applications are analyzed and compared with the present availability of these materials. A seri...

H. J. Spitzer

1974-01-01

131

The Thin Oil Film Equation  

NASA Technical Reports Server (NTRS)

A thin film of oil on a surface responds primarily to the wall shear stress generated on that surface by a three-dimensional flow. The oil film is also subject to wall pressure gradients, surface tension effects and gravity. The partial differential equation governing the oil film flow is shown to be related to Burgers' equation. Analytical and numerical methods for solving the thin oil film equation are presented. A direct numerical solver is developed where the wall shear stress variation on the surface is known and which solves for the oil film thickness spatial and time variation on the surface. An inverse numerical solver is also developed where the oil film thickness spatial variation over the surface at two discrete times is known and which solves for the wall shear stress variation over the test surface. A One-Time-Level inverse solver is also demonstrated. The inverse numerical solver provides a mathematically rigorous basis for an improved form of a wall shear stress instrument suitable for application to complex three-dimensional flows. To demonstrate the complexity of flows for which these oil film methods are now suitable, extensive examination is accomplished for these analytical and numerical methods as applied to a thin oil film in the vicinity of a three-dimensional saddle of separation.

Brown, James L.; Naughton, Jonathan W.

1999-01-01

132

Microwave Absorption Studies on HIGH-Tc Superconductors and Related Materials VINON-RESONANT Microwave Absorption in Ultra-Thin Bi-Sr-Ca-Cu-O FILMS  

NASA Astrophysics Data System (ADS)

Non-resonant microwave absorption (NRMA) studies have been done for Bi-Sr-Ca-Cu-O (BSCCO) films with thicknesses of 30 and 15 fabricated on MgO substrate by MOCVD. For the latter two kinds of samples have been fabricated: BSCCO/MgO and BiOx/BSCCO/MgO. NRMA signals have been detected up to about 70-75 K for all the samples. The lower critical magnetic field Hc1* of the 30 film was severely increased by the application of a magnetic field of several kGauss, whereas it is almost unaffected in the case of 15 films. Hc1* increases but the signal intensity decreases with increasing temperature for all the 30 and 15 samples. The temperature dependence of the intensity is quite different from that of thicker films (100 and 350 ), in which the intensity vs. temperature relation has a peak (or peaks) at particular temperature(s).

Sugawara, K.; Sugimoto, T.; Baar, D. J.; Shiohara, Y.; Tanaka, S.

133

Chemical preparation of powders and films for high temperature superconductors  

NASA Astrophysics Data System (ADS)

A precipitation process has been developed to prepare precursor powders which can be calcined and sintered to form high critical temperature superconductors such as YBa(sub 2)Cu(sub 3)O(sub 7-x). Precursor powders are prepared using a continuous precipitation system in which a solution containing highly soluble salts of the desired metal cations is rapidly and completely mixed with a solution containing precipitating anions such as hydroxide and carbonate ions. The resulting amorphous powder can be calcined to form submicron particles of desired superconducting phases which are useful in preparing inks for the ink-jet printing of superconducting interconnects. The powders can be redissolved in organic solvents to form solutions which can be used in spin or dip coating substrates with thin superconducting films. Finally, the powders have been used to prepare bulk ceramics which exhibit the highest reported critical currents of any chem-prep ceramics. Bulk samples prepared from chloride doped precursors exhibit large, oriented grains and extensive flux pinning.

Bunker, B. C.; Voigt, J. A.; Lamppa, D. L.; Doughty, D. H.; Venturini, E. L.; Kwak, J. F.; Ginley, D. S.; Headley, T. J.; Harrington, M. S.; Eatough, M. O.

134

Thin-film forces in pseudoemulsion films  

SciTech Connect

Use of foam for enhanced oil recovery (EOR) has shown recent success in steam-flooding field applications. Foam can also provide an effective barrier against gas coning in thin oil zones. Both of these applications stem from the unique mobility-control properties a stable foam possesses when it exists in porous media. Unfortunately, oil has a major destabilizing effect on foam. Therefore, it is important for EOR applications to understand how oil destroys foam. Studies all indicate that stabilization of the pseudoemulsion film is critical to maintain foam stability in the presence of oil. Hence, to aid in design of surfactant formulations for foam insensitivity to oil the authors pursue direct measurement of the thin-film or disjoining forces that stabilize pseudoemulsion films. Experimental procedures and preliminary results are described.

Bergeron, V.; Radke, C.J. [California Univ., Berkeley, CA (United States). Dept. of Chemical Engineering]|[Lawrence Berkeley Lab., CA (United States)

1991-06-01

135

Thin films under chemical stress  

SciTech Connect

The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

Not Available

1991-01-01

136

Low work function, stable thin films  

DOEpatents

Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

2000-01-01

137

Thin film-coated polymer webs  

DOEpatents

The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

Wenz, Robert P. (Cottage Grove, MN); Weber, Michael F. (Shoreview, MN); Arudi, Ravindra L. (Woodbury, MN)

1992-02-04

138

Semiconducting Polymers for Thin?Film Electronics  

Microsoft Academic Search

An overview of practical issues related to the adoption of semiconducting polymers in thin?film electronic devices is presented. Performance requirements for organic light emitting diodes, thin?film transistors and photovoltaic devices are reviewed.

Michael L. Chabinyc

2006-01-01

139

Multi-gigawatt thin film PV  

Microsoft Academic Search

Thin films are reaching 1-GW annual production because of the success of one company and technology, First Solar CdTe. Other thin films languish, with amorphous and thin film silicon still restrained by low efficiencies; and CIS yet to demonstrate sufficient volume production. Will the future of thin films be only the future of CdTe? Yet even with commercial success, CdTe

Ken Zweibel

2009-01-01

140

Microwave response of high transition temperature superconducting thin films  

NASA Technical Reports Server (NTRS)

We have studied the microwave response of YBa2Cu3O(7 - delta), Bi-Sr-Ca-Cu-O, and Tl-Ba-Ca-Cu-O high transition temperature superconducting (HTS) thin films by performing power transmission measurements. These measurements were carried out in the temperature range of 300 K to 20 K and at frequencies within the range of 30 to 40 GHz. Through these measurements we have determined the magnetic penetration depth (lambda), the complex conductivity (sigma(sup *) = sigma(sub 1) - j sigma(sub 2)) and the surface resistance (R(sub s)). An estimate of the intrinsic penetration depth (lambda approx. 121 nm) for the YBa2Cu3O(7 - delta) HTS has been obtained from the film thickness dependence of lambda. This value compares favorably with the best values reported so far (approx. 140 nm) in single crystals and high quality c-axis oriented thin films. Furthermore, it was observed that our technique is sensitive to the intrinsic anisotropy of lambda in this superconductor. Values of lambda are also reported for Bi-based and Tl-based thin films. We observed that for the three types of superconductors, both sigma(sub 1) and sigma(sub 2) increased when cooling the films below their transition temperature. The measured R(sub s) are in good agreement with other R(sub S) values obtained using resonant activity techniques if we assume a quadratic frequency dependence. Our analysis shows that, of the three types of HTS films studied, the YBa2Cu3O(7 - delta) thin film, deposited by laser ablation and off-axis magnetron sputtering are the most promising for microwave applications.

Miranda, Felix Antonio

1991-01-01

141

Properties of epitaxial SrRuO3 thin films  

NASA Astrophysics Data System (ADS)

SrRuO3 thin films were deposited on (100) LaAlO3 using pulsed laser deposition. The films were (001) oriented normal to the substrate surface with a high degree of in-plane orientation with respect to the substrate's major axes. An ion beam minimum yield of 2.5 percent was obtained for the films, indicating high crystallinity. The films exhibited metallic behavior with a room temperature resistivity of about 200 mW cm. A kink in the resistivity, corresponding to a ferromagnetic phase transition, was observed at about 160 K. It was found that SrRuO3 is structurally and chemically compatible with the YBCO superconductors. High quality YBCO films were obtained on SrRuO3 LaAlO3. Multilayers of YBCO/SrRuO3 were successfully fabricated.

Wu, X. D.; Foltyn, S. R.; Dye, R. C.; Coulter, Y.; Muenchausen, R. E.

1993-05-01

142

Thin film polymeric gel electrolytes  

DOEpatents

Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

1996-12-31

143

Thin film polymeric gel electrolytes  

DOEpatents

Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

1996-01-01

144

Thin Film Piezoelectrics for MEMS  

Microsoft Academic Search

Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements. This paper reviews the literature in this field, with an emphasis on the factors that

S. Trolier-McKinstry; P. Muralt

2004-01-01

145

Thin crystal film optical components  

NASA Astrophysics Data System (ADS)

We developed new production method for thin (0.3 - 1.0 micron) crystalline film (TCF) coating. Method comprises three steps: first, deposition of solvent based liquid crystalline ink on the surface in thin (10 micron) layer, second, orientation of the liquid by laminar shear flow in desirable direction, drying/crystallization of the laser into submicron thin solid crystalline layer. Final solid crystalline layer can be chemically modified. TCF has properties that defined by properties of molecular materials that are used for liquid crystalline ink. Liquid crystalline ink is ordered media with highly none-linear dependence of viscosity upon shear stress. Application of stress produces orientation of liquid crystal and high viscosity preserves order in drying process. hear flow direction determines the direction of crystallographic axes in crystal thin film. Film has monoclinic symmetry with relatively high defect concentration. Flat molecules of aromatic organic dyes are packed in layered crystalline structure with flat plane oriented perpendicular to the surface of the substrate. In present paper we describe properties of TCF with anisotropy of absorption and birefringence. TCF is highly optically anisotropic film with refraction coefficient difference between ordinary and extraordinary directions up to (Delta) n equals 0.8 in the visible spectrum and (Delta) n equals 0.3 at 1550 nm. Dichroic dyes with narrow band absorption in different areas of UV, visible and IR spectra allow to produce polarizers and retarders with new color band design flexibility.

Ignatov, Leonid; Lazarev, Pavel I.; Ovchinnikova, Natalya; Paukshto, Michael

2002-01-01

146

Lessons from Oxypnictide Thin Films  

NASA Astrophysics Data System (ADS)

First experiments on the growth of oxypnictide F-doped LaFeAsO thin films indicated an incomplete normal-to-superconducting transition and offered a work programme challenging to overcome possible difficulties in their fabrication. In this regard the possibility of an all in-situ epitaxial growth appeared to be a matter of time and growth parameters. The following review clarifies that F-doped oxypnictide thin films are extremely difficult to grow by in-situ PLD due to the formation of very stable impurity phases such as oxyfluorides (LaOF) and oxides (La2O3) and the loss of stoichiometry possibly due to incongruent evaporation of the target or re-evaporation of volatile elements at the substrate surface. However, the review also demonstrates that the employed two-step fabrication process for oxypnictide thin films has been successfully applied in the preparation of clean polycrystalline as well as of epitaxial thin films. Fundamental investigations on the upper critical field, its temperature dependence and its anisotropy contributed to an understanding of multiband superconductivity in oxypnictides.

Haindl, Silvia; Kidszun, Martin; Onken, Franziska; Mietke, Alexander; Thersleff, Thomas

2013-02-01

147

Oxidation of thin scandium films  

Microsoft Academic Search

Thin Sc films (namely, 20 layers or thinner) are studied as a function of oxygen exposure using Auger Electron Spectroscopy (AES) and Temperature Programmed Desorption (TPD) measurements. While AES data indicate that surface Sc layers oxidize rapidly, TPD data indicate that at room temperature the oxidation process is confined to the top layers. The surface oxide layer, about 5 layers

A. Shih; J. E Yater; C Hor; R Abrams

2003-01-01

148

Thin Film Solid Lubricant Development  

NASA Technical Reports Server (NTRS)

Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

Benoy, Patricia A.

1997-01-01

149

MOCVD-SrTiO3 thin film microwave coplanar tunable devices: modelling of varactors  

Microsoft Academic Search

SrTiO3 (STO) ferroelectric (FE) thin films associated with High Temperature Superconductor (HTSC) is a good compromise to realize electronically tunable microwave devices combining tunable dielectric properties of FE films with low loss microwave conductivity in HTSC. STO, which exhibits a perovskite structure, is suitable for epitaxial growth of YBaCuO films and has been widely studied to realize tunable components around

A Gensbittel; A F Dgardin; A J Kreisler

2008-01-01

150

Critical magnetic field of V/sub 3/Ga thin films with third element additions  

SciTech Connect

We have made thin films of V-Ga superconductors by electron beam codeposition with approximately one percent additions of Nb, Ta, Sn, Pt or Pb. We have measured the high-magnetic field properties of these films to observe the effect of these impurities on spin-orbit scattering. Although the residual resistivity of the films was affected by the additional elements, the rate of spin-orbit scattering did not appear to increase.

Tedrow, P.M.; Bending, S.J.; Hammond, R.; Meservey, R.; Tkaczyk, J.E.

1985-03-01

151

Application of YIG film to thin film inductors  

Microsoft Academic Search

The application of YIG (yttrium iron garnet) films to thin film inductors is examined up to 1 GHz. The application of a YIG film to thin film inductors made it possible to increase the inductance without increasing the stray capacitance. The sandwich-type YIG inductor exhibited an inductance 40 times larger than that of a similar air core inductor. The inductance

K. I. Arai; M. Yamaguchi; H. Ohzeki; M. Matsumoto

1991-01-01

152

Sputtered Thin Film Research.  

National Technical Information Service (NTIS)

The reactive rf sputtering technique was applied to the preparation of a wide variety of materials. Single crystal films of ZnO, TiO2, WO3 AlN and GaN were grown on one or more of the insulating crystalline substrates of Al2O3, MgAl2O3, SiC and LiNbO3. Da...

A. J. Shuskus D. E. Cullen D. J. Quinn E. L. Paradis J. M. Berak

1974-01-01

153

High permittivity thin film nanolaminates  

NASA Astrophysics Data System (ADS)

Thin (~10 nm) films comprising of Ta2O5-HfO2, Ta2O5-ZrO2, and ZrO2-HfO2 nanolaminates were deposited and characterized for possible gate dielectric applications. These films were deposited on silicon substrates using atomic layer deposition. The dielectric constants of these films were in 12-14 range and the leakage currents in 2.610-8-4.210-7 A/cm2 range at 1 MV/cm electric field. It was found that as these films were made thinner, the value of their dielectric constant dropped compared to their bulk values. The dominant leakage current mechanism at low electric fields was determined to be Schottky emission, whereas Poole-Frenkel emission dominated at higher fields.

Zhang, H.; Solanki, R.; Roberds, B.; Bai, G.; Banerjee, I.

2000-02-01

154

Thin-Film Metamaterials Called Sculptured Thin Films  

Microsoft Academic Search

\\u000a Morphology and performance are conjointed attributes of metamaterials, of which sculptured thin films (STFs) are examples.\\u000a STFs are assemblies of nanowires that can be fabricated from many different materials, typically via physical vapor deposition\\u000a onto rotating substrates. The curvilinear-nanowire morphology of STFs is determined by the substrate motions during fabrication.\\u000a The optical properties, especially, can be tailored by varying the

Akhlesh Lakhtakia; Joseph B. Geddes III

2010-01-01

155

Sputter deposition for multi-component thin films  

DOEpatents

Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams. 10 figs.

Krauss, A.R.; Auciello, O.

1990-05-08

156

Sputter deposition for multi-component thin films  

DOEpatents

Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams.

Krauss, Alan R. (Plainfield, IL); Auciello, Orlando (Cary, NC)

1990-01-01

157

Thin film buried anode battery  

DOEpatents

A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

Lee, Se-Hee (Lakewood, CO); Tracy, C. Edwin (Golden, CO); Liu, Ping (Denver, CO)

2009-12-15

158

Thin-Film Selective Emitter  

NASA Technical Reports Server (NTRS)

Direct conversion of thermal energy into electrical energy using a photovoltaic cell is called thermophotovoltaic energy conversion. One way to make this an efficient process is to have the thermal energy source be an efficient selective emitter of radiation. The emission must be near the band-gap energy of the photovoltaic cell. One possible method to achieve an efficient selective emitter is the use of a thin film of rare-earth oxides. The determination of the efficiency of such an emitter requires analysis of the spectral emittance of the thin film including scattering and reflectance at the vacuum-film and film-substrate interfaces. Emitter efficiencies (power emitted in emission band/total emitted power) in the range 0.35-0.7 are predicted. There is an optimum optical depth to obtain maximum efficiency. High emitter efficiencies are attained only for low (less than 0.05) substrate emittance values, both with and without scattering. The low substrate emittance required for high efficiency limits the choice of substrate materials to highly reflective metals or high-transmission materials such as sapphire.

Chubb, Donald L.; Lowe, Roland A.

1993-01-01

159

Patterns and conformations in molecularly thin films  

Microsoft Academic Search

Molecularly thin films have been a subject of great interest for the last several years because of their large variety of industrial applications ranging from micro-electronics to bio-medicine. Additionally, molecularly thin films can be used as good models for biomembrane and other systems where surfaces are critical. Many different kinds of molecules can make stable films. My research has considered

Prem B. Basnet

2010-01-01

160

Electrochemically deposited bismuth telluride thin films  

Microsoft Academic Search

Thin films of bismuth telluride grown by electrochemical deposition technique on conducting glass and Mo sheet substrates, were characterized for their structural, morphological, optical and compositional analysis. These studies revealed polycrystalline anisotropic and layered structure of these films with different compositional stoichiometry. In the present work electrochemical deposition of bismuth telluride thin films is studied as a dopant material in

Santosh Golia; M. Arora; R. K. Sharma; A. C. Rastogi

2003-01-01

161

Preparation of thin ceramic films via an aqueous solution route  

DOEpatents

A new chemical method of forming thin ceramic films has been developed. An aqueous solution of metal nitrates or other soluble metal salts and a low molecular weight amino acid is coated onto a substrate and pyrolyzed. The amino acid serves to prevent precipitation of individual solution components, forming a very viscous, glass-like material as excess water is evaporated. Using metal nitrates and glycine, the method has been demonstrated for zirconia with various levels of yttria stabilization, for lanthanum-strontium chromites, and for yttrium-barium-copper oxide superconductors on various substrates.

Pederson, Larry R. (Kennewick, WA); Chick, Lawrence A. (Richland, WA); Exarhos, Gregory J. (Richland, WA)

1989-01-01

162

Preparation and characterization of hollandite thin film  

Microsoft Academic Search

Thin films of hollandite-type KxGaxSn8?xO16 (KGSO) were prepared by spin-coating method. Favorite thin films were obtained using YSZ substrate. Those are colorless, transparent and smooth, and about 100150 nm thick at minimum, consisting of KGSO primary particles with a few tens of nanometers in average size. The adsorption behavior of NO on the thin film was examined by diffuse reflectance

Kenjiro Fujimoto; Jun Suzuki; Toshiyuki Mori; Mamoru Watanabe

2002-01-01

163

Thin-Film Silicon PV Technology  

Microsoft Academic Search

Thin-film silicon solar cell technology is one of the promising photovoltaic technologies for delivering low-cost solar electricity. Today the thin-film silicon PV market (402MWp produced in 2008) is dominated by amorphous silicon based modules; however it is expected that the tandem amorphous\\/microcrystalline silicon modules will take over in near future. Solar cell structures based on thin-film silicon for obtaining high

Miroslav Zeman

2010-01-01

164

Method of producing amorphous thin films  

DOEpatents

Disclosed is a method of producing thin films by sintering which comprises: (a) coating a substrate with a thin film of an inorganic glass forming material possessing the capability of being sintered; and (b) irradiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof. Also disclosed is the article produced by the method claimed. 4 figs.

Brusasco, R.M.

1992-09-01

165

Method of producing amorphous thin films  

DOEpatents

Disclosed is a method of producing thin films by sintering which comprises: a. coating a substrate with a thin film of an inorganic glass forming parulate material possessing the capability of being sintered, and b. irridiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof. Also disclosed is the article produced by the method claimed.

Brusasco, Raymond M. (Livermore, CA) [Livermore, CA

1992-01-01

166

Doping in zinc oxide thin films  

Microsoft Academic Search

Doping in zinc oxide (ZnO) thin films is discussed in this dissertation. The optimizations of undoped ZnO thin film growth using molecular-beam epitaxy (MBE) are discussed. The effect of the oxygen ECR plasma power on the growth rate, structural, electrical, and optical properties of the ZnO thin films were studied. It was found that larger ECR power leads to higher

Zheng Yang

2009-01-01

167

High-Temperature-Superconductor Films In Microwave Circuits  

NASA Technical Reports Server (NTRS)

Report discusses recent developments in continuing research on fabrication and characterization of thin films of high-temperature superconducting material and incorporation of such films into microwave circuits. Research motivated by prospect of exploiting superconductivity to reduce electrical losses and thereby enhancing performance of such critical microwave components as ring resonators, filters, transmission lines, phase shifters, and feed lines in phased-array antennas.

Bhasin, K. B.; Warner, J. D.; Romanofsky, R. R.; Heinen, V. O.; Chorey, C. M.

1993-01-01

168

Thin films, asphaltenes, and reservoir wettability.  

National Technical Information Service (NTIS)

Reservoir wettability impacts the success of oil recovery by waterflooding and other methods. To understand wettability and its alteration, thin-film forces in solid-aqueous-oil systems must be elucidated. Upon rupture of thick aqueous films separating th...

R. Kaminsky V. Bergeron C. J. Radke

1993-01-01

169

Analysis of Hard Thin Film Coating  

NASA Technical Reports Server (NTRS)

Marshall Space Flight Center (MSFC) is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) to deposit hard thin film on stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

Shen, Dashen

1998-01-01

170

Analysis of Hard Thin Film Coating  

NASA Technical Reports Server (NTRS)

MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

Shen, Dashen

1998-01-01

171

Nb3Al thin film deposition for low-noise terahertz electronics  

NASA Astrophysics Data System (ADS)

Higher energy gap superconducting materials were always interesting for low-noise mixer applications such as superconductor-insulator-superconductor tunnel junctions (SIS) and hot-electron bolometer (HEB) used in sub-millimeter and terahertz parts of electro-magnetic spectrum. Here, we report a novel approach for producing Nb3Al thin film by co-sputtering from two confocally arranged Nb and Al dc-magnetrons onto substrate heated up to 830C. Characterization of the deposited films revealed presence of the A15 phase and measured critical temperature was up to 15.7 K with the transition width 0.2-0.3 K for a 300 nm thick film. We measured the film critical magnetic field and studied influence of annealing on the film properties. We have investigated compositional depth profile of the deposited films by spectroscopy of reflected electrons.

Dochev, D.; Pavolotsky, A. B.; Belitsky, V.; Olofsson, H.

2008-02-01

172

Transport of thin superconducting films and multilayer heterostructure made by Atomic layer deposition  

NASA Astrophysics Data System (ADS)

We report the use of atomic layer deposition (ALD) to synthesize thin superconducting films and multilayer superconductor-insulator (S-I) heterostructures. The ALD technique applied to superconducting films opens the way for a variety of applications, including improving the performance and decreasing the cost of high energy particle accelerators, superconducting wires for energy storage, and bolometers for radiation detection. Furthermore, the atomic-scale thickness control afforded by ALD enables the study of superconductivity and associated phenomena in homogeneous layers in the ultra-thin film limit. In this respect, we will present results of ALD-grown transition metal-based superconductors, including nitrides, carbides, and silicides of niobium, nitrides of molybdenum and titanium, and Nb1-xTixN/AlN-based S-I heterostructures. Transport measurement for various composition and film thicknesses will be presented.

Proslier, Thomas; Klug, Jeffrey; Groll, Nickolas; Becker, Nicholas; Glatz, Andreas; Vinokur, Valerii; Pellin, Michael; Baturina, Tatyana; Elam, Jeffrey; Zasadzsinki, John

2013-03-01

173

Fabrication and characterization of amorphous lithium electrolyte thin films and rechargeable thin-film batteries  

SciTech Connect

Research on the deposition and characterization of amorphous lithium electrolyte and vanadium oxide thin films was undertaken with the goal of developing a thin-film rechargeable lithium battery. Most of this effort has focused on the electrolyte film, with less but increasing attention given to the cathode. Recent studies on these films and rechargeable thin-film lithium cells will be reviewed in this paper.

Bates, J.B.; Dudney, N.J.; Gruzalski, G.R.; Zuhr, R.A.; Choudhury, A.; Luck, C.F. [Oak Ridge National Lab., TN (United States); Robertson, J.D. [Kentucky Univ., Lexington, KY (United States)

1992-02-01

174

Thin film fuel cell electrodes.  

NASA Technical Reports Server (NTRS)

Earlier work shows that fuel cell electrodes prepared by sputtering thin films of platinum on porous vycor substrates avoid diffusion limitations even at high current densities. The presented study shows that the specific activity of sputtered platinum is not unusually high. Performance limitations are found to be controlled by physical processes, even at low loadings. Catalyst activity is strongly influenced by platinum sputtering parameters, which seemingly change the surface area of the catalyst layer. The use of porous nickel as a substrate shows that pore size of the substrate is an important parameter. It is noted that electrode performance increases with increasing loading for catalyst layers up to two microns thick, thus showing the physical properties of the sputtered layer to be different from platinum foil. Electrode performance is also sensitive to changing differential pressure across the electrode. The application of sputtered catalyst layers to fuel cell matrices for the purpose of obtaining thin total cells appears feasible.

Asher, W. J.; Batzold, J. S.

1972-01-01

175

Thin film solar energy collector  

DOEpatents

A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

Aykan, Kamran (Monmouth Beach, NJ); Farrauto, Robert J. (Westfield, NJ); Jefferson, Clinton F. (Millburn, NJ); Lanam, Richard D. (Westfield, NJ)

1983-11-22

176

Thin film electrochemical power cells  

NASA Astrophysics Data System (ADS)

Fundamental properties of research cells were correlated with the projected performance of full scale power sources, considering both battery and supercapacitor concepts. In addition to establishing the data base for modelling and performance projections, the program had the additional objective of identifying loss mechanisms and degradation reactions, especially those unique to polymer thin film cell designs. Because of the intrinsic high electrode/electrolyte interface areas, interfacial reactions must be understood. Many applications require power under extreme conditions, and low temperature performance needs to be improved.

Owens, Boone B.; Smyrl, William H.

1991-08-01

177

Electroactive controlled release thin films  

PubMed Central

We present the fabrication of nanoscale electroactive thin films that can be engineered to undergo remotely controlled dissolution in the presence of a small applied voltage (+1.25 V) to release precise quantities of chemical agents. These films, which are assembled by using a nontoxic, FDA-approved, electroactive material known as Prussian Blue, are stable enough to release a fraction of their contents after the application of a voltage and then to restabilize upon its removal. As a result, it is possible to externally trigger agent release, exert control over the relative quantity of agents released from a film, and release multiple doses from one or more films in a single solution. These electroactive systems may be rapidly and conformally coated onto a wide range of substrates without regard to size, shape, or chemical composition, and as such they may find use in a host of new applications in drug delivery as well as the related fields of tissue engineering, medical diagnostics, and chemical detection.

Wood, Kris C.; Zacharia, Nicole S.; Schmidt, Daniel J.; Wrightman, Stefani N.; Andaya, Brian J.; Hammond, Paula T.

2008-01-01

178

A Electron Tunneling Study of TIN(1-X) Copper(x) Amorphous Thin Films  

Microsoft Academic Search

Amorphous Sn_{1-x}Cu _{x} thin films (0.08 <= x <= 0.41) were prepared by e-beam deposition onto a liquid helium temperature substrate in an ultra-high vacuum system to form tunnel junctions in an aluminum - aluminum oxide - superconductor configuration. Measurements of film resistance, transition temperature, crystallization temperature, and energy gap were made. The Eliashberg function, alpha^2F(omega), was derived from tunneling

Paul Willard Watson III

1993-01-01

179

Vortices in a Superconducting Thin Film Observed by Polarized Neutron Reflectivity  

Microsoft Academic Search

We have demonstrated that vortices in a thin film superconductor can be observed by spin-polarized neutron specular reflectivity. The effect arises because the presence of vortices change the neutron optical potential. We will discuss the result of experiments which were performed on a 6000thick c-axis film of YBa_2Cu_3O_7-x with the magnetic field applied parallel to the surface. A model will

S.-W. Han; J. Ankner; H. Kaiser; P. F. Miceli; E. Paraoanu; L. H. Greene

1998-01-01

180

Nb films sputtered with a (Ar, H2) mixture and application to superconductor-insulator-superconductor junctions  

Microsoft Academic Search

Effects of hydrogen trapping in Nb base electrodes on the superconductivity of Nb itself and superconductor-insulator-superconductor (SIS) junction characteristics have been investigated. The Nb films were prepared by sputter deposition in an atmosphere of (Ar, H2) mixture. The gap parameter ?Nb and the critical temperature Tc gradually decreased with increasing H2 partial pressure. The SIS junctions exhibited a sudden extinction

Takeshi Kobayashi; Ken Sakuta; Kazuo Fujisawa

1985-01-01

181

Photoluminescence study of Cupric Telluride thin films  

NASA Astrophysics Data System (ADS)

Thin films of Cupric Telluride (CuTe) of thickness from 50 nm to 150 nm have been prepared by thermal evaporation technique onto well-cleaned glass substrates kept at 300 K under the vacuum better than 210-5 mbar. After annealing the deposited films at 375 K for one-hour, the photoluminescence spectra of CuTe thin film was recorded. The X ray diffraction analysis confirmed the composition and polycrystalline nature of CuTe films. The grain size of CuTe thin film, estimated by Atomic Force Microscopy (AFM) measurements, is around 40 nm. From Photoluminescence spectra, a strong emission peak at visible range was observed for all the films. Further a shift in the peak position was observed for the CuTe thin films of 150 nm thickness. The observed PL spectra were attributed to confinement effect.

Neyvasagam, K.; Muralidharan, G.; Vasu, V.; Soundararajan, N.

2008-04-01

182

Electro-deposition of superconductor oxide films  

DOEpatents

Methods for preparing high quality superconducting oxide precursors which are well suited for further oxidation and annealing to form superconducting oxide films. The method comprises forming a multilayered superconducting precursor on a substrate by providing an electrodeposition bath comprising an electrolyte medium and a substrate electrode, and providing to the bath a plurality of precursor metal salts which are capable of exhibiting superconducting properties upon subsequent treatment. The superconducting precursor is then formed by electrodepositing a first electrodeposited (ED) layer onto the substrate electrode, followed by depositing a layer of silver onto the first electrodeposited (ED) layer, and then electrodepositing a second electrodeposited (ED) layer onto the Ag layer. The multilayered superconducting precursor is suitable for oxidation at a sufficient annealing temperature in air or an oxygen-containing atmosphere to form a crystalline superconducting oxide film.

Bhattacharya, Raghu N. (Littleton, CO)

2001-01-01

183

High Tc superconductivity; Thin films and applications; Proceedings of the Meeting, San Diego, CA, Mar. 20, 21, 1990  

NASA Astrophysics Data System (ADS)

Various papers on high-Tc superconductivity in thin films and applications are presented. Individual topics addressed include: preparation of high-Tc YBa2Cu3O(7-x) thin films, study of epitaxial YBa2Cu3O(x) films, electrochemical deposition of high-Tc superconducting thin films, relative surface stoichiometry of high-Tc materials by total reflection X-ray fluorescence, preparation and properties YBa2Cu3O(7-x) thin-film SQUIDs, Si-coupled superconducting FETs using microfabrication technologies, enhanced critical currents by high-pressure impregnation of 1-2-3 systems with normal conductors. Also discussed are: YBaCuO thin films used as electrical switch or current limiter, optically triggered switching of superconducting YBa2Cu3O7 thin films, high-Tc superconducting thin films as optical radiation detectors, MBE as a path to novel high-Tc superconductors, ion-beam codeposition of HTSC films on SrTiO3 and ITO/Si, plasma luminescence spectroscopy for sputtering growth of high-Tc superconductors, barium diffusion in metalloorganic solution deposited barrier layers and Y1Ba2Cu3O(7-x) films.

Chi, Cheng-Chung; van Dover, R. Bruce

184

New Use of Thin Film Light Detector.  

National Technical Information Service (NTIS)

The new use of a metal-insulator-metal (MIM) structure having a thin film base and a thin film insulator is reported. This structure provides a sensitive light detector with or without a bias. The insulator provides a trapezoidal barrier instead of the Sc...

G. W. Lewicki J. Maserjian

1972-01-01

185

Heat Transfer in Thin Liquid Films.  

National Technical Information Service (NTIS)

The objective of this summer research was to examine heat transfer in thin liquid films. A successful formulation was accomplished on the effect of electrostatic field on the stability of isothermal non-evaporating thin films and on the heat transfer in e...

R. S. Gorla L. W. Byrd

1996-01-01

186

Hydrothermal epitaxy of perovskite thin films  

Microsoft Academic Search

This work details the discovery and study of a new process for the growth of epitaxial single crystal thin films which we call hydrothermal epitaxy. Hydrothermal epitaxy is a low temperature solution route for producing heteroepitaxial thin films through the use of solution chemistry and structurally similar substrates. The application of this synthesis route has led to the growth of

Allen T. Chien

1998-01-01

187

Thin film shape memory alloy microactuators  

Microsoft Academic Search

Thin film shape memory alloys (SMAs) have the potential to become a primary actuating mechanism for mechanical devices with dimensions in the micron-to-millimeter range requiring large forces over long displacements. The work output per volume of thin film SMA microactuators exceeds that of other microactuation mechanisms such as electrostatic, magnetic, thermal bimorph, piezoelectric, and thermopneumatic, and it is possible to

P. Krulevitch; A. P. Lee; P. B. Ramsey; J. C. Trevino; M. A. Northrup

1996-01-01

188

Multiferroics: progress and prospects in thin films  

Microsoft Academic Search

Multiferroic materials, which show simultaneous ferroelectric and magnetic ordering, exhibit unusual physical properties - and in turn promise new device applications - as a result of the coupling between their dual order parameters. We review recent progress in the growth, characterization and understanding of thin-film multiferroics. The availability of high-quality thin-film multiferroics makes it easier to tailor their properties through

R. Ramesh; Nicola A. Spaldin

2007-01-01

189

Electrostatic thin film chemical and biological sensor  

DOEpatents

A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

Prelas, Mark A. (Columbia, MO); Ghosh, Tushar K. (Columbia, MO); Tompson, Jr., Robert V. (Columbia, MO); Viswanath, Dabir (Columbia, MO); Loyalka, Sudarshan K. (Columbia, MO)

2010-01-19

190

Effect of Substrate Composition on the Piezoelectric Response of Reactively Sputtered AlN Thin Films;Thin Solid Films.  

National Technical Information Service (NTIS)

Effect of substrate composition on the piezoelectric response of reactively sputtered AIN thin films of reactive radio frequency (RF) sputtered AIN thin films. We observed piezoelectric deposition of adjacent thin film layers appeared to have the greatest...

P. G. Clem D. B. Dimos D. M. Gonzales J. A. Ruffner B. A. Tuttle

1999-01-01

191

New Detection Scheme for Novel Superconductors  

Microsoft Academic Search

Most of the recently discovered superconductors have a complicated stochiometry, e.g. high Tc cuprates. In order to facilitate the discovery of new superconductors we developed a detection scheme, which combines a wide variety of stochiometries with a very sensitive probe of superconductivity. We grow phase spread alloy thin films using several sputtering guns simultaneously. These films have a continously varying

A. Hoffmann; B. Knigge; D. Lederman; D. C. Vier; D. Mendoza; S. Schultz; Ivan K. Schuller

1996-01-01

192

Cellulose triacetate, thin film dielectric capacitor  

NASA Technical Reports Server (NTRS)

Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

1995-01-01

193

Cellulose triacetate, thin film dielectric capacitor  

NASA Technical Reports Server (NTRS)

Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

1993-01-01

194

Preparation and Characterization of PZT Thin Films  

SciTech Connect

In analogy with Piezoelectric Wafer Active Sensors (PWAS), Lead Zirconate Titanate (PZT) thin films also seem to be promising for Structural Health Monitoring (SHM) due to a number of reasons. Firstly, PZT thin films with well oriented domains show enhanced piezoelectric response. Secondly, PWAS requires comparatively large voltage leading to a demand for thin PZT films (<< {mu}m in thickness) for low voltage operation at {<=}10 V. This work focuses on two different aspects: (a) growing oriented PZT thin films in ferroelectric perovskite phase in the range of (80-150) nm thickness on epitaxial Si/Pt without a seed layer and (b) synthesizing perovskite phase in PZT thin films on Corning glass 1737 using a seed layer of TiO{sub x} (TiO{sub x} thickness ranging between 30 nm to 500 nm)

Bose, A.; Sreemany, M.; Bhattacharyya, D. K.; Sen, Suchitra [Central Glass and Ceramic Research Institute, CSIR, 196 Raja S.C. Mullick Road, Kolkata-700032 (India); Halder, S. K. [National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110012 (India)

2008-07-29

195

A monolithic thin film electrochromic window  

NASA Astrophysics Data System (ADS)

Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community.

Goldner, R. B.; Arntz, F. O.; Berera, G.; Haas, T. E.; Wong, K. K.; Wei, G.; Yu, P. C.

196

A monolithic thin film electrochromic window  

SciTech Connect

Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. [Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center; Wei, G. [Mobil Solar Energy Corp., Billerica, MA (United States); Yu, P.C. [PPG Industries, Inc., Monroeville, PA (United States)

1991-12-31

197

A monolithic thin film electrochromic window  

SciTech Connect

Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. (Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center); Wei, G. (Mobil Solar Energy Corp., Billerica, MA (United States)); Yu, P.C. (PPG Industries, Inc., Monroeville, PA (United States))

1991-01-01

198

Photoresponse of ion-beam-deposited Y-Ba-Cu-O thin films  

SciTech Connect

We report on the microstructure and photoresponse of ion-beam-deposited Y-Ba-Cu-O granular thin films. High-temperature superconductor thin films of the average composition YBa{sub 1.8}Cu{sub 3.6}O{sub {ital x}} were ion-beam deposited onto yttria-stabilized zirconia and strontium titanate substrates from a composite target. Post-annealing processes were used to control the degree of granularity in these films, and led to films which varied in superconducting behavior. The microstructures of these films were studied by secondary electron microscopy and Auger analysis. Photoresponse and resistivity were measured as a function of temperature. We found that the degree of granularity in our films correlates with their resistivity and photoresponse which are similar to those of epitaxial or granular films.

Li, K.; Hsiao, R.; Tang, C. (Boeing Aerospace and Electronics, High Technology Center, Seattle, WA (USA))

1990-09-15

199

Growth and Synthesis of Nanostructured Thin Films  

Microsoft Academic Search

Nanostructured thin film (NSTF) is composed of thin layers of nanostructured objects such as nanoparticles, nanorods, nanotubes,\\u000a nanowires, and nanoporous networks. Fabrication and synthesis of those nanostructured thin films are essential for exploring\\u000a their properties and creating advanced applications. This chapter gives an overview of a range of synthesis methods for NSTFs,\\u000a such as thermal vapor transport methods, catalyst-assisted fabrication

Yiping Zhao

200

Ferroelectric Thin Films for Electronic Applications  

Microsoft Academic Search

This study yokes together the feasibility of a family of PbO-based perovskite-structured ferroelectric thin films as functional elements in nonvolatile random access memories (NVRAMs), in high capacity dynamic RAMs, and in a new class of flexure wave piezoelectric ultrasonic micromotors. The dielectric and ferroelectric properties of lead zirconate titanate (PZT) thin films were dependent on thickness; at saturation, the films

K. R. Udayakumar

1993-01-01

201

Infrared radiation of thin plastic films.  

NASA Technical Reports Server (NTRS)

A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.

Tien, C. L.; Chan, C. K.; Cunnington, G. R.

1972-01-01

202

Characterization of C and C thin films  

Microsoft Academic Search

The authors have produced several grams of Buckministerfullerene. From this, they were able to separate out both pure C and pure C using the Trough`n`Brew Purification method. These fullerenes will be made into thin films on insulating and metal substrates. Recent fullerene film characterizations, including electrical conductivity and photoconductivity, have all been made on films containing mixtures of C and

J. C. Castle; G. J. Coram; N. J. Halas

1992-01-01

203

Electrochromism in copper oxide thin films.  

National Technical Information Service (NTIS)

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline e...

T. J. Richardson J. L. Slack M. D. Rubin

2000-01-01

204

Nitrogen Doped Zinc Oxide Thin Film.  

National Technical Information Service (NTIS)

To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO(sub 2) plasma or by N(sup+) implantation. All ZnO films grown show n-type conductivity. In unintentional...

S. X. Z. Li

2003-01-01

205

BDS thin film damage competition  

SciTech Connect

A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

Stolz, C J; Thomas, M D; Griffin, A J

2008-10-24

206

Primary research efforts on exploring the commercial possibilities of thin film growth and materials purification in space  

NASA Technical Reports Server (NTRS)

The progress made on research programs in the 1987 to 1988 year is reported. The research is aimed at producing thin film semiconductors and superconductor materials in space. Sophisticated vacuum chambers and equipment were attained for the epitaxial thin film growth of semiconductors, metals and superconductors. In order to grow the best possible epitaxial films at the lowest possible temperatures on earth, materials are being isoelectronically doped during growth. It was found that isoelectrically doped film shows the highest mobility in comparison with films grown at optimal temperatures. Success was also attained in growing epitaxial films of InSb on sapphire which show promise for infrared sensitive devices in the III-V semiconductor system.

1989-01-01

207

Development of High TCR Platinum Thin Films  

NASA Astrophysics Data System (ADS)

High Temperature Coefficient of Resistance (TCR) platinum (Pt) thin films become increasingly attractive for devices with Micro Electro Mechanical Systems (MEMS) using high temperature. However, in annealing with high temperature, Pt thin films are degraded, and in comparison with bulk Pt, the TCR of Pt thin films are inferior. In this study, alumina (Al2O3) buffer layers were introduced between the silicon nitride (SiNx) films and Pt films. After annealing in the air, the structure of Pt thin films was observed by Scanning Electron Microscope (SEM) and analyzed by X-ray diffraction, and the depth-resolved elemental composition of interface between Pt thin films and Al2O3 buffer layers was observed by Secondary Ion Mass Spectrometry (SIMS). As the annealing temperature is higher, the grain size of Pt is larger. At the point of the largest grain size, the largest TCR could not obtain. In this paper, we discuss about the relationship between the structure of Pt thin film and annealing temperature, and about the effect of Al2O3 buffer layers.

Yamashita, Akira; Ohji, Hiroshi; Fukami, Tatsuya; Tsutsumi, Kazuhiko

208

Micromotors using magnetostrictive thin films  

NASA Astrophysics Data System (ADS)

This study deals with a micromotor based on the use of magnetostrictive thin films. This motor belongs to the category of the Standing Wave Ultrasonic Motors. The active part of the motor is the rotor, which is a 100 micrometers thick ring vibrating in a flexural mode. Teeth (300 micrometers high) are placed on special positions of the rotor and produce an oblique motion which can induce the relative motion of any object in contact with them. The magnetic excitation field is radial and uses the transverse coupling of the 4 micrometers thick magnetostrictive film. The film, deposited by sputtering on the ring, consists of layers of different rare-earth/iron alloys and was developed during a European Brite-Euram project. The finite element technique was used in order to design a prototype of the motor and to optimize the active rotor and the energizer coil. The prototype we built delivered a speed of 30 turns per minute with a torque of 2 (mu) N.m (without prestress applied on the rotor). Our experimental results show that the performance of this motor could easily be increased by a factor of 5. The main advantage of this motor is the fact that it is remotely powered and controlled. The excitation coil, which provides both power and control, can be placed away from the active rotor. Moreover, the rotor is completely wireless and is not connected to its support or to any other part. It is interesting to note that it would not be possible to build this type of motor using piezoelectric technology. Medical applications of magnetostrictive micromotors could be found for internal microdistributors of medication (the coil staying outside the body). Other applications include remote control micropositioning, micropositioning of optical components, and for the actuation of systems such as valves, electrical switches, and relays.

Claeyssen, F.; Le Letty, R.; Barillot, F.; Betz, Jochen; Mackay, Ken; Givord, Dominique; Bouchilloux, Philippe

1998-07-01

209

Deposition and characterization of thin HTS and magnetic perovskite films  

NASA Astrophysics Data System (ADS)

The in-situ growth and physical properties were investigated of thin films and bilayers of high-temperature superconductors (HTS) YBa2Cu3O7 (YBCO) and ferromagnetic (FM) manganites La0.7Sr0.3MnO3 (LSMO) and La0.7Ca0.3MnO3 (LCMO) with thicknesses of several tens of nm obtained by magnetron sputtering. Similar twin structures were observed by an optical microscope in areas on the LaAlO3 substrate surface void of films, in areas containing YBCO, in LSMO films, and in YBCO/LCMO bilayers, although the main spatial period of the twin structure seemed to be slightly different in the areas containing the LSMO film. The resistance (and its temperature dependence) of the LCMO films strongly depends on the annealing conditions. The resistance of the LSMO and LCMO films grown on Al2O3 substrates decreased as the temperature (T) was increased in the lower and higher temperature ranges, and increased as T was increased at medium temperatures.

Blagoev, B. S.; Gostev, I. G.; Nurgaliev, T. K.; Strbik, V.; Bineva, I. E.; Uspenskaya, L.; Mateev, E. S.; Neshkov, L.; Dobro?ka, E.; Chromik, .

2014-05-01

210

Thin-film rechargeable lithium batteries  

SciTech Connect

Small thin-film rechargeable cells have been fabricated with a lithium phosphorus oxyniuide electrolyte, Li metal anode, and Li{sub 1-x}Mn{sub 2}O{sub 4} as the cathode film. The cathode films were fabricated by several different techniques resulting in both crystalline and amorphous films. These were compared by observing the cell discharge behavior. Estimates have been made for the scale-up of such a thin-film battery to meet the specifications for the electric vehicle application. The specific energy, energy density, and cycle life are expected to meet the USABC mid-term criteria. However, the areas of the thin-films needed to fabricate such a cell are very large. The required areas could be greatly reduced by operating the battery at temperatures near 100{degrees}C or by enhancing the lithium ion transport rate in the cathode material.

Dudney, N.J.; Bates, J.B.; Lubben, D.

1994-11-01

211

Tantalum oxide thin films for microelectronic applications  

Microsoft Academic Search

Over the last several years, tantalum pentoxide (Ta2O5) thin films have received much attention as chip integrated high permittivity, high breakdown strength dielectrics for storage capacitors for ULSI DRAMs. We have studied the properties of reactively sputtered films of Ta2O5 on silicon wafers. These films have been characterized for refractive index. X-ray diffraction studies on films annealed in oxygen ambient

Fang-Xing Jiang; S. K. Kurinec

1995-01-01

212

Electrochromism in copper oxide thin films  

Microsoft Academic Search

Transparent thin films of copper(I) oxide prepared on conductive SnO2\\/F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a

T. J. Richardson; J. L. Slack; M. D. Rubin

2001-01-01

213

Electrochromism in copper oxide thin films  

Microsoft Academic Search

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a

T. J. Richardson; J. L. Slack; M. D. Rubin

2000-01-01

214

Flexible thin metal film thermal sensing system  

NASA Technical Reports Server (NTRS)

A flexible thin metal film thermal sensing system is provided. A self-metallized polymeric film has a polymeric film region and a metal surface disposed thereon. A layer of electrically-conductive metal is deposited directly onto the self-metallized polymeric film's metal surface. Coupled to at least one of the metal surface and the layer of electrically-conductive metal is a device/system for measuring an electrical characteristic associated therewith as an indication of temperature.

Thomsen, Donald L. (Inventor)

2010-01-01

215

Electrical properties of tellurium thin films  

Microsoft Academic Search

Semiconducting properties of evaporated tellurium thin films, in the thickness range of 100 to 400 , are studied and correlated with observed structural properties. It is found that less-than-monolayer gold films can act as nucleation sites and stimulate the growth of large crystallites in deposited Te films. The Au-nucleated Te films are preferentially oriented with the c axis in the

ROBERT W. DUTTON; RICHARD S. MULLER

1971-01-01

216

Transparent Conducting Thin Films for Spacecraft Applications.  

National Technical Information Service (NTIS)

Transparent conductive thin films are required for a variety of optoelectronic applications: automotive and aircraft windows, and solar cells for space applications. Transparent conductive coatings of indium-tin-oxide (ITO)-magnesium fluoride (MgF2) and a...

M. E. Perez-davis T. Malave-sanabria P. Hambourger S. K. Rutledge D. Roig

1994-01-01

217

Interaction of Thin Erbium Films with Aluminum.  

National Technical Information Service (NTIS)

Aluminum is a potential substrate to support thin erbium films used for high-temperature, hydrogen isotope storage. Both aluminum and erbium are reactive metals, and the interaction of the two could make for an unstable combination at elevated temperature...

D. M. Holloway E. P. Boespflug J. L. Provo J. M. Harris

1984-01-01

218

Semiconductor- Nanocrystal/Conjugated Polymer Thin Films.  

National Technical Information Service (NTIS)

The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the ...

A. P. Allvisatos D. Milliron J. J. Dittmer W. U. Huynh

2005-01-01

219

Chemically-Deposited Thin Ferrite Films.  

National Technical Information Service (NTIS)

Thin ferrite and garnet films have been prepared by chemically depositing stoichiometric ratios of alcoholic solutions of metal nitrates with divalent and trivalent cations onto ceramic substrates which were then subjected to a firing cycle to form the de...

W. L. Wade T. Collins W. J. Skudera R. Stern

1965-01-01

220

Thin film production method and apparatus  

DOEpatents

A method for forming a thin film material which comprises depositing solid particles from a flowing suspension or aerosol onto a filter and next adhering the solid particles to a second substrate using an adhesive.

Loutfy, Raouf O. (Tucson, AZ); Moravsky, Alexander P. (Tucson, AZ); Hassen, Charles N. (Tucson, AZ)

2010-08-10

221

Conjugated Polymer Doped Nanocomposite Silica Thin Films.  

National Technical Information Service (NTIS)

The present invention discloses a composite structure including an inorganic thin film having a defined mesostructure formed in a surfactant based formation process including a non-cationic surfactant template material, and, a conjugated polymer immobiliz...

A. M. Dattelbaum A. P. Shreve H. L. Wang

2004-01-01

222

Analysis of Hydrogen Isotopes in Thin Films.  

National Technical Information Service (NTIS)

Mass spectrometer modifications made for high resolution analysis of hydrogen isotopes outgassed from occluder thin films are described. The electronic modifications made to the source, magnet power supply, and scanning circuits have provided increased pr...

J. O. Humphries T. K. Mehrhoff

1976-01-01

223

Electrochemical fabrication of nanoporous polypyrrole thin films  

Microsoft Academic Search

Polypyrrole thin films with pores in nanometer scale were synthesized by direct electrochemical oxidation of pyrrole in a mixed electrolyte of isopropyl alcohol, boron trifluoride diethyl etherate, sodium dodecylsulfonate and poly(ethylene glycol) using well-aligned ZnO nanowires arrays as templates. The thin films exhibit high conductivity of ca. ?rt ?20.5s\\/cm and can be driven to bend during redox processes in 1.0M

Mei Li; Jinying Yuan; Gaoquan Shi

2008-01-01

224

Pentacene thin film transistors and inverter circuits  

Microsoft Academic Search

Organic thin film transistors and simple electronic circuits have been fabricated using the fused-ring small-molecule aromatic hydrocarbon pentacene as the active material. Carrier field-effect mobilities greater than 0.2 cm2\\/V-s were obtained for thin film transistors fabricated on glass using low-temperature ion-beam deposited silicon dioxide as the gate dielectric and thermally evaporated pentacene as the active material. Using similar transistors, integrated

Hagen Klauk; Yen-Yi Lin; David J. Gundlach; Thomas N. Jackson

1997-01-01

225

Electrical properties of cerium fluoride thin films  

Microsoft Academic Search

Thin films of ionic conductors have low internal resistance. Hence, it could be used as an electrolyte material in sensors\\u000a to operate at ambient temperatures. Cerium fluoride, a unipolar fluoride ion conductor, has got a different application in\\u000a electrochemical sensor. In the present work, cerium fluoride thin films have been prepared by physical vapor deposition method\\u000a and their electrical properties

Arun Kumar Dorai; S. Selvasekarapandian; Nithya Hellar; Sakunthala Ayyasamy; Hema Muthusamy

2010-01-01

226

Thin-film reliability and engineering overview  

NASA Technical Reports Server (NTRS)

The reliability and engineering technology base required for thin film solar energy conversions modules is discussed. The emphasis is on the integration of amorphous silicon cells into power modules. The effort is being coordinated with SERI's thin film cell research activities as part of DOE's Amorphous Silicon Program. Program concentration is on temperature humidity reliability research, glass breaking strength research, point defect system analysis, hot spot heating assessment, and electrical measurements technology.

Ross, R. G., Jr.

1984-01-01

227

Ultrasonic Spraying Thin Films of Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

Carbon nanotubes have many interesting and useful properties, especially in terms of strength and electrical conductivity. However, they can be hard to work with because they are held together in bundles by strong Van der Waals forces. Much work has been performed in the ultrasonic spraying of liquid suspensions of single and multi-wall carbon nanotubes. The resulting thin films have a variety of applications, including electron transport in thin film photovoltaics.

Willey, Anthony; Davis, Robert; Vanfleet, Richard; Balls, Amy; Abbott, Jonathan

2011-10-01

228

Sculptured thin films II. Experiments and applications  

Microsoft Academic Search

A report on the preparation and potential applications of sculptured thin films (STFs) is presented. STFs are nano-engineered\\u000a columnar thin films in which the columnar direction can made to change easily and often during growth. STFs of virtually any\\u000a material can be prepared through directional vapor deposition onto any surface under low adatom-mobility conditions. Columnar\\u000a shapes, such as zig-zag, C-,

R. Messier; Akhlesh Lakhtakia

1999-01-01

229

Thin film solar cells for indoor use  

Microsoft Academic Search

The effect of low irradiance for thin film solar cells is investigated in this work. First, a-Si:H\\/CIGS\\/DSSC\\/OPV four kinds of thin film solar cells are fabricated and measured with the sun simulator (AM 1.5G, 100 mW\\/cm2). Then, the saturation current density J0 is extracted from the Voc and Jsc. Spectral irradiance of the desk light, LED light, sun light at

P. C. Yang; I. M. Chan; C. H. Lin; Y. L. Chang

2011-01-01

230

Epitaxial thin-film Si solar cells  

Microsoft Academic Search

Most types of thin-film solar cells imply a radical departure from the dominant bulk crystalline Si technology. This is not the case for epitaxial thin-film solar cells. In this technology, a high quality Si layer is deposited epitaxially on a low-cost Si substrate (e.g. cast Upgraded Metallurgical Grade silicon or high-throughput Si ribbons) and processed into a solar cell. This

G. Beaucarne; F. Duerinckx; I. Kuzma; K. Van Nieuwenhuysen; H. J. Kim; J. Poortmans

2006-01-01

231

Superconducting thin films on potassium tantalate substrates  

Microsoft Academic Search

This patent describes a composition for the lossless transmission of electrical current, it comprises: a superconducting thin film epitaxially deposited on a oriented surface of a single crystal KTa{sub 1-z}NbO substrate, where z is 0 to 1, wherein the superconducting thin film is selected from the group consisting of YBaCuO, YBaCuO, a compound wherein a trivalent rare earth element replaces

R. Feenstra; L. A. Boatner

1992-01-01

232

Recent developments in thin film solar cells  

Microsoft Academic Search

The present status of the development of thin film solar cells is reviewed, with emphasis on important areas for further research. The following aperture-area efficiencies were measured for thin film modules: a-Si:H, 9.8 percent, 933 sq cm; CuIn(Ga)Se2, 11.1 percent, 938 sq cm; and CdTe, 7.3 percent, 838 sq cm. CuIn(Ga)Se2 cells and modules demonstrated excellent efficiencies and stability. The

Neelkanth G. Dhere

1990-01-01

233

Radiation effects on thin film solar cells  

Microsoft Academic Search

A study has been undertaken to assess the effects of 1 MeV electron radiation on two types of thin film solar cells, thin-film silicon:hydrogen alloy (TFS) and copper indium diselenide (CIS). Using TFS devices with efficiencies between 8-9% AM 0 (9-10% AM 1.5), and CIS devices with efficiencies between 7-8% AM 0 (8-9% AM 1.5), the results show the devices

C. F. Gay; B. E. Anspaugh; R. R. Potter; D. P. Tanner

1984-01-01

234

Biomimetic Pathways for Assembling Inorganic Thin Films  

Microsoft Academic Search

Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100^circC and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic

I. A. Aksay; M. Trau; S. Manne; I. Honma; N. Yao; L. Zhou; P. Fenter; P. M. Eisenberger; S. M. Gruner

1996-01-01

235

Combinatorial Arc Plasma Deposition of Thin Films  

NASA Astrophysics Data System (ADS)

In this paper, we introduce a new combinatorial thin film deposition process that uses arc plasma [combinatorial arc plasma deposition (CAPD)]. The major goal of CAPD in this study is to search for new compositions of amorphous thin film alloys. CAPD uses three cathodic arc plasma guns and the guns shoot the pulse like plasma one by one at a specific time interval. The plasma from each gun is guided onto a substrate by a magnetic field at a specific area on the substrate so as to deposit a compositionally-graded thin film. The deposited thin film is separated into 1,089 samples (the size of each is 1 1 mm2) by a trench grid on the substrate. The samples together are called the thin film library and all samples are numbered by the 5-bit row and column marks in the grid. To prove CAPD, a thin film library of a Pd-Cu-Si alloy system was deposited. The composition and non crystallinity of 180 samples were evaluated using energy-dispersive X-ray fluorescence spectrometer (EDX) and imaging-plate X-ray diffractometer (IP-XRD), respectively. Both measurements were performed without detaching the samples from the library. Analysis of 180 samples showed a graded composition, and some of the samples were shown to be amorphous.

Hata, Seiichi; Yamauchi, Ryusuke; Sakurai, Junpei; Shimokohbe, Akira

2006-04-01

236

Printable CIGS thin film solar cells  

NASA Astrophysics Data System (ADS)

Among the various thin film solar cells in the market, CuInGaSe thin film solar cells have been considered as the most promising alternatives to crystalline silicon solar cells because of their high photo-electricity conversion efficiency, reliability, and stability. However, many fabrication methods of CIGS thin film are based on vacuum processes such as evaporation and sputtering techniques which are not cost efficient. This work develops a solution method using paste or ink liquid spin-coated on glass that would be competitive to conventional ways in terms of cost effective, non-vacuum needed, and quick processing. A mixture precursor was prepared by dissolving appropriate amounts of composition chemicals. After the mixture solution was cooled, a viscous paste was prepared and ready for spin-coating process. A slight bluish CIG thin film on substrate was then put in a tube furnace with evaporation of metal Se followed by depositing CdS layer and ZnO nanoparticle thin film coating to complete a solar cell fabrication. Structure, absorption spectrum, and photo-electricity conversion efficiency for the as-grown CIGS thin film solar cell are under study.

Fan, Xiaojuan

2013-03-01

237

Laser applications in thin-film photovoltaics  

NASA Astrophysics Data System (ADS)

We review laser applications in thin-film photovoltaics (thin-film Si, CdTe, and Cu(In,Ga)Se2 solar cells). Lasers are applied in this growing field to manufacture modules, to monitor Si deposition processes, and to characterize opto-electrical properties of thin films. Unlike traditional panels based on crystalline silicon wafers, the individual cells of a thin-film photovoltaic module can be serially interconnected by laser scribing during fabrication. Laser scribing applications are described in detail, while other laser-based fabrication processes, such as laser-induced crystallization and pulsed laser deposition, are briefly reviewed. Lasers are also integrated into various diagnostic tools to analyze the composition of chemical vapors during deposition of Si thin films. Silane (SiH4), silane radicals (SiH3, SiH2, SiH, Si), and Si nanoparticles have all been monitored inside chemical vapor deposition systems. Finally, we review various thin-film characterization methods, in which lasers are implemented.

Bartlome, R.; Strahm, B.; Sinquin, Y.; Feltrin, A.; Ballif, C.

2010-08-01

238

Photophysical properties of Alq3 thin films  

NASA Astrophysics Data System (ADS)

This work contains investigation results of the photophysical properties of aluminum (III) tris(8-hydroxyquinoline) thin films. The Alq3 thin films were successfully fabricated by Physical Vapor Deposition technique. The films were grown on transparent: (quartz and glass) and semiconductor (n-type silica) substrates kept at room temperature during the deposition process. Selected films were annealed after fabrication in ambient atmosphere for 12 h at the temperature equal to 100 C and 150 C. Morphology of the films was investigated by AFM technique. Photophysical properties were characterized via photoluminescence, transmission, second and third harmonic generation measurements. The thin films exhibit high structural quality regardless of the annealing process, but the stability of the film can be improved by using an appropriate temperature during the annealing process. Photoluminescence of Alq3 films obtained in air were efficient and stable. The measurements of transmission, SHG and THG spectra allowed us to determine optical constant of the films. We find that the photophysical properties were strictly connected with the morphology and the annealing process significantly changes the structural properties of the films.

Zawadzka, A.; P?ciennik, P.; Strzelecki, J.; ?ukasiak, Z.; Sahraoui, B.

2013-11-01

239

Aging in Thin Metallic Films.  

National Technical Information Service (NTIS)

Low magnetostriction NiFe and NiFe based ternary films 220A and 340A thick were prepared by thermal evaporation and bias sputtering. A few evaporated films were sputter etched. The films were aged in air with a magnetic bias in the plane of the film and p...

H. R. Irons W. E. Anderson L. J. Schwee

1978-01-01

240

RF surface resistance of YBa2Cu3O(7-x) thin films  

NASA Technical Reports Server (NTRS)

The excitement engendered by the discovery of the new T sub c oxide superconductors has led to much speculation about practical applications of thin films of these materials in digital and analog electronic devices. Most of these envisioned applications involve high frequency signals for which a detailed knowledge of the surface impedance of the novel superconductors is very important. We have measured the surface resistance of thin films of YBaCuO in the frequency range 0.5 less than f less than 17 GHz using a stripline-resonator method. The stripline procedure also was used to measure the surface resistance of high quality gold and aluminum films; the resistance values obtained agree with values predicted from the measured dc resistance using the Pippard formalism for the anomalous skin effect. The YBaCuO were produced by a multilayer deposition process. The films are formed by e-beam evaporation of 24 layers of Y, Ba, and Cu. Films with the highest transition temperature were obtained using yttria-stabilized zirconia (YSZ) substrates. After deposition, the films are transferred to a furnace where they are annealed in flowing O2 at 850 C for 2h. The furnace then is turned off and allowed to cool to 100 C in about 16 h. Auger profiling of the films made by this process shows that the concentrations of Y, Ba, Cu, and O are uniform to within 1 percent throughout the thickness of the film.

1988-01-01

241

Thin transparent films formed from powdered glass  

NASA Technical Reports Server (NTRS)

Glass film less than five mils thick is formed from powdered glass dispersed in an organic liquid, deposited on a substrate, and fused into place. The thin films can be cut and shaped for contact lenses, optical filters and insulating layers.

1965-01-01

242

REACTIVELY SPUTTERED VANADIUM DIOXIDE THIN FILMS  

Microsoft Academic Search

Thin films of vanadium dioxide have been formed by reactive sputtering of vanadium in an argon atmosphere doped with a partial pressure of oxygen. The films were deposited on sapphire substrates held at 400C and exhibit a highly oriented polycrystalline monoclinic structure at room temperature. The semiconductor to metal transition is observed at 345K with a slight hysteresis with temperature

E. N. Fuls; D. H. Hensler; A. R. Ross

1967-01-01

243

Evaporated Silicon Thin-Film Transistors.  

National Technical Information Service (NTIS)

The method of fabrication, the theory and properties of evaporated silicon thin-film transistors are discussed. The device consists of a p-type silicon film (0.5-2 microns thick) on a sapphire substrate, with aluminum source-drain electrodes evaporated on...

C. A. T. Salama L. Young

1966-01-01

244

Evaporated Silicon Thin-Film Transistors.  

National Technical Information Service (NTIS)

Preliminary results on thin-film transistors having evaporated silicon films on sapphire are described. The silicon is evaporated first onto the sapphire substrate and is followed by the aluminum source-drain electrodes. The silicon oxide SiOx insulator i...

C. A. T. Salama L. Young

1965-01-01

245

Phase Transitions in Thin Block Copolymer Films  

Microsoft Academic Search

David Turnbull's experiments and theoretical insights paved the way for much of our modern understanding of phase transitions in materials. In recognition of his contributions, this lecture will concentrate on phase transitions in a material system not considered by Turnbull, thin diblock copolymer films. Well-ordered block copolymer films are attracting increasing interest as we attempt to extend photolithography to smaller

Edward J

2010-01-01

246

Low-cost thin film pressure transducer  

Microsoft Academic Search

A flat diaphragm type pressure transducer with an anodised insulating layer and thin Pt-film as a strain gauge has been designed and made. The paper gives details of the diaphragm and the information on the anodisation process employed. Sputtering was used for the deposition of the Pt-film strain gauge sensors. Observations on the behaviour of the transducer are presented which

K Rajanna; MM Nayak; R Krishnamurthy; S Mohan

1997-01-01

247

Electrical Switching in Lithium Niobate Thin Films.  

National Technical Information Service (NTIS)

The ferroelectric switching properties of thin films of lithium niobate (LiNbO3) on silicon have been investigated. The polarization is shown to be partially reversible with an applied electric field at room temperature. The samples were films of LiNbO3 w...

T. A. Rost H. Lin T. A. Rabson

1991-01-01

248

Ternary Compound Thin Film Solar Cells.  

National Technical Information Service (NTIS)

This research program is directed toward the growth and characterization of I-III-V1 sub 2 ternary compound thin films and the use of these films in the development of photovoltaic devices for terrestrial application. The materials under investigation are...

L. L. Kazmerski

1976-01-01

249

Microwave properties of HTS (high temperature superconductor) films  

SciTech Connect

High-frequency applications of high-temperature superconductors generally fall into two categories: devices that require low values of surface resistance R{sub s} in ambient surface magnetic fields H{sub rf}, and devices that require low R{sub s} in modest fields. Moreover, many applications can be realized with small-surface-area films whereas others require larger areas-radiofrequency (rf) cavities, for example. Regardless of the application, the potential of HTS films is predicated on satisfying one or both of the above-stated requirements. We have measured the surface resistance of small-area (1 cm{sup 2}) and large-area (6.5 cm{sup 2}) YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) films that have been laser ablated onto LaA{ell}O{sub 3} substrates, large-area (5.1 cm{sup 2}) YBCO films that have been e-beam deposited onto LaA{ell}O{sub 3}, and large-area (11.4 cm{sup 2}) T{ell}-based films that have been magnetron sputtered onto metallic substrates. The best R{sub s} values are obtained from the 1-cm{sup 2} laser-ablated films; they are 40 {mu}{Omega} and 340 {mu}{Omega} at 4 K and 77 K, respectively ({omega}/2{pi} = 10 GHz). Comparable values for Cu are 6 and 13 m{Omega}, respectively. Large-area T{ell}-based films yield typical R{sub s} values of 4 m{Omega} and 14 m{Omega} at 4 K and 77 K, respectively ({omega}/2{pi} = 18 GHz). The dependence of R{sub s} on H{sub rf} for these films indicates that surface fields as large as 55 Oe can be achieved with R{sub s} increasing only by a factor of 10. This field dependence is associated with c-axis texturing.

Cooke, D.W.; Arendt, P.N.; Gray, E.R.; Muenchausen, R.E.; Bennett, B.L.; Foltyn, S.R.; Estler, R.C.; Wu, X.D.; Reeves, G.A.; Elliott, N.E.; Brown, D.R. (Los Alamos National Lab., NM (USA)); Portis, A.M. (California Univ., Berkeley, CA (USA)); Taber, R.C. (Hewlett-Packard Corp., Palo Alto, CA (USA). Labs.); Mogro-Campero, A. (General Electric Co., Schenectady, NY (USA). Corporate Research and Development Ce

1990-01-01

250

Transport phase diagram for superconducting thin films of tantalum with homogeneous disorder  

Microsoft Academic Search

We have constructed a phase diagram in temperature-magnetic-field-disorder space for homogeneously disordered superconducting Ta thin films. We identify the phases by measuring nonlinear transport characteristics that are known to be unique in each phase. The resulting phase diagram shows that the superconducting phase is completely surrounded by the intervening metallic phase prohibiting a direct superconductor-insulator transition at any disorder.

Yize Li; Carlos L. Vicente; Jongsoo Yoon

2010-01-01

251

A proposal of epitaxial oxide thin film structures for future oxide electronics  

Microsoft Academic Search

New epitaxial oxide thin film structures are proposed Cor future oxide electronics, particularly tor ferroelectric random access memory (FeRAM) with oxide electrodes drawing on silicon-on-insulator (SOI) and high-Tc superconductor technology. These structures have a benefical effect in device scaling and ferroelectric size effect and can he a starting point for future oxide electronics, such as high-Tc. superconducting, ferroelectric, piezoelectric and

M. Suzuki; T. Ami

1996-01-01

252

All thin film magnetoelectric magnetic field sensors  

Microsoft Academic Search

We have fabricated prototype ac magnetic field sensors operating at room temperature based on all thin film ME devices showing strong magnetoelectric (ME) coupling. The ME layers consist of a sol-gel derived Pb(Zr0.52Ti0.48)TiO3 (PZT) film and a dc magnetron sputter deposited magnetostrictive Fe70Ga30 (FeGa) film. The bilayer structures are prepared on micromachined Si wafers, and the laser cutting technique is

Peng Zhao

2009-01-01

253

Flexible Thin Metal Film Thermal Sensing System  

NASA Technical Reports Server (NTRS)

A flexible thin metal film thermal sensing system is provided. A thermally-conductive film made from a thermally-insulating material is doped with thermally-conductive material. At least one layer of electrically-conductive metal is deposited directly onto a surface of the thermally-conductive film. One or more devices are coupled to the layer(s) to measure an electrical characteristic associated therewith as an indication of temperature.

Thomsen, Donald Laurence (Inventor)

2012-01-01

254

Annealing behavior of electroplated permalloy thin films  

Microsoft Academic Search

The isochronal annealing behavior of electroplated 1.2 ?m Ni-Fe thin films containing nominally 80 wt% Ni, in the temperature\\u000a range from 373? to 773?K, and with a magnetic field parallel to the easy axis of the films, was investigated through measurements\\u000a of the films structural, magnetic and electrical properties. The effects of annealing could be described in terms of two

R. L. Anderson; A. Gangulee; L. T. Romankiw

1973-01-01

255

Chalcopyrite thin film solar cells by electrodeposition  

Microsoft Academic Search

This paper reviews the state of the art in using electrodeposition to prepare chalcopyrite absorber layers in thin film solar cells. Most of the studies deal with the direct preparation of Cu(In,Ga)Se2 films, and show that the introduction of gallium in the films is now becoming possible from single bath containing all the elements. Electrodeposition can also be used to

D. Lincot; J. F. Guillemoles; S. Taunier; D. Guimard; J. Sicx-Kurdi; A. Chaumont; O. Roussel; O. Ramdani; C. Hubert; J. P. Fauvarque; N. Bodereau; L. Parissi; P. Panheleux; P. Fanouillere; N. Naghavi; P. P. Grand; M. Benfarah; P. Mogensen; O. Kerrec

2004-01-01

256

Polysilicon Super-Thin-Film Transistor (SFT)  

Microsoft Academic Search

N-channel MOS FET's have been fabricated in super-thin polysilicon film on quartz substrate. The thickness of the film had an important role in improving the electrical properties. Moreover, grain boundary passivation by the hydrogen from a plasma-SiN film has been developed to increase the field effect mobility. The field effect mobility is more than 20 cm2\\/V\\\\cdots at the polysilicon thickness

Hisao Hayashi; Takashi Noguchi; Takefumi Oshima

1984-01-01

257

Thin monocrystalline silicon films for solar cells  

Microsoft Academic Search

Thin film monocrystalline silicon solar cells based on porous silicon layer transfer processes could be cost-effective because of their lower consumption of material use and the potential for high efficiency. Novel techniques of porous silicon film separation, obtained by anodization of silicon, are presented. Anodization techniques for porous silicon film separation are classified as either one-step or two-step. Two-step anodization

C. S. Solanki; R. R. Bilyalov; G. Beaucarne; J. Poortmans

2003-01-01

258

Simulation of the delamination of thin films  

NASA Astrophysics Data System (ADS)

We simulate thin film delamination using a lattice springs model. We use this model to construct a phase diagram of different delamination behaviours, produced by varying the compression of the film and also the radius to which local relaxation is allowed to take place about failing bonds. From this we see a progression from laminar and linear behaviours to radial and rounded features as compressive stress is increased. Sinusoidal telephone cord behaviour occurs only at a small range of fairly low stresses, and thin films.

Scarle, S.; Ewels, C. P.; Heggie, M. I.

2005-08-01

259

Thin-film rechargeable lithium batteries  

SciTech Connect

Thin-film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin-film battery.

Dudney, N.J.; Bates, J.B.; Lubben, D. [Oak Ridge National Lab., TN (United States). Solid State Div.

1995-06-01

260

Electrostatic tuning of the properties of disordered indium-oxide films near the superconductor-insulator transition  

NASA Astrophysics Data System (ADS)

The evolution with carrier concentration of the electrical properties of amorphous indium oxide (InOx) thin films has been studied using electric double-layer transistor configurations. Carrier variations of up to 71014carriers/cm2 were achieved using an ionic liquid as a gate dielectric. The superconductor-insulator transition was traversed, and the magnitude and position of the large magnetoresistance peak found in the insulating regime were modified. The systematic variation of the magnetoresistance peak with charge concentration was found to be qualitatively consistent with a simulation based on a model involving granularity.

Lee, Yeonbae; Frydman, Aviad; Chen, Tianran; Skinner, Brian; Goldman, A. M.

2013-07-01

261

Magnetoelectric thin film composites with interdigital electrodes  

NASA Astrophysics Data System (ADS)

Magnetoelectric (ME) thin film composites on silicon cantilevers are fabricated using Pb(Zr0.52Ti0.45)O3 (PZT) films with interdigital transducer electrodes on the top side and FeCoSiB amorphous magnetostrictive thin films on the backside. These composites without any direct interface between the piezoelectric and magnetostrictive phase are superior to conventional plate capacitor-type thin film ME composites. A limit of detection of 2.6 pT/Hz1/2 at the mechanical resonance is determined which corresponds to an improvement of a factor of approximately 2.8 compared to the best plate type sensor using AlN as the piezoelectric phase and even a factor of approximately 4 for a PZT plate capacitor.

Piorra, A.; Jahns, R.; Teliban, I.; Gugat, J. L.; Gerken, M.; Knchel, R.; Quandt, E.

2013-07-01

262

Self-organized superconducting textures in thin films.  

SciTech Connect

The interplay between the superconducting order parameter and elastic fields, which are intimately connected to the very existence of the superconductivity itself, can result in a novel superconducting state: a regular self-organized texture of superconducting islands. We study the formation of these islands in a system of a thin superconducting film coupled elastically to a more rigid substrate and derive the phase diagram below the superconducting critical temperature depending on the elastic coupling constant of both subsystems. The fact that this pattern is a result of the Ginzburg-Landau description of superconductivity indicates that the formation of regular structures may be a common feature of the superconductor transition in the presence of long-range coupling.

Glatz, A.; Aranson, I.; Vinokur, V. M.; Chtchelkatchev, N. M.; Baturina, T. I. (Materials Science Division); (Russian Academy of Sciences); (Moscow Inst. of Physics and Technology); (Inst. Semiconductor Physics); (Novosibirsk State Univ.)

2011-07-07

263

Formation and investigation of nanostructured thin films  

NASA Astrophysics Data System (ADS)

Small devices, in the range of nanometers, are playing a major role in today's technology. The field of nanotechnology is concerned with materials and systems whose structures and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena and processes due to their small nanoscale size. Researches more and more are finding that structural features in the range of about 1 to 100 nanometers behave quite differently than isolated molecules (1 nanometer) or bulk materials. For comparison, a 10 nanometer structure is 1000 times smaller than the diameter of a human hair. The virtues of working in the nanodomain are increasingly recognized by the scientific community and discussed in the popular press. The use of such devices is expected to revolutionize our industries and lives. This work mainly focuses on the fabrication, characterization and discovery of new nanostructured thin films. This research consists of the design of a new high-deposition rate nanoparticle machine for depositing nanostructured films from beams of nanoparticles and investigation film's unique optical and physical properties. A high-deposition rate nanoparticle machine was designed, built and successfully tested. Different nanostructured thin films were deposited from Copper, Gold, Iron and Zirconium targets with the grain size of between 1 to 20 nm under different conditions. Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), and x-ray diffraction (XRD) confirmed nanoscale grain size structures of deposited films. The optical properties of the nanostructured films deposited from copper, Iron and Zirconium targets were significantly different from optical properties of bulk and thin films. Zr, Cu and Fe films were transparent. Gold films revealed an epitaxial contact with the silicon substrate with interesting crystal structures. The new high-deposition rate nanoparticle machine was able to deposit new nanostructured films with different properties from bulk and thin films reported in the literatures.

Khabari, Ali

264

MOF thin films: existing and future applications.  

PubMed

The applications and potentials of thin film coatings of metal-organic frameworks (MOFs) supported on various substrates are discussed in this critical review. Because the demand for fabricating such porous coatings is rather obvious, in the past years several synthesis schemes have been developed for the preparation of thin porous MOF films. Interestingly, although this is an emerging field seeing a rapid development a number of different applications on MOF films were either already demonstrated or have been proposed. This review focuses on the fabrication of continuous, thin porous films, either supported on solid substrates or as free-standing membranes. The availability of such two-dimensional types of porous coatings opened the door for a number of new perspectives for functionalizing surfaces. Also for the porous materials themselves, the availability of a solid support to which the MOF-films are rigidly (in a mechanical sense) anchored provides access to applications not available for the typical MOF powders with particle sizes of a few ?m. We will also address some of the potential and applications of thin films in different fields like luminescence, QCM-based sensors, optoelectronics, gas separation and catalysis. A separate chapter has been devoted to the delamination of MOF thin films and discusses the potential to use them as free-standing membranes or as nano-containers. The review also demonstrates the possibility of using MOF thin films as model systems for detailed studies on MOF-related phenomena, e.g. adsorption and diffusion of small molecules into MOFs as well as the formation mechanism of MOFs (101 references). PMID:21225034

Shekhah, O; Liu, J; Fischer, R A; Wll, Ch

2011-02-01

265

Size effects in superconducting thin films coupled to a substrate  

NASA Astrophysics Data System (ADS)

Recent experimental advances in surface science have made it possible to track the evolution of superconductivity in films as the thickness enters the nanoscale region where it is expected that the substrate plays an important role. Here, we put forward a mean-field, analytically tractable, model that describes size effects in ultrathin films coupled to the substrate. We restrict our study to one-band, crystalline, weakly coupled superconductors with no impurities. The thin-film substrate/vacuum interfaces are described by a simple asymmetric potential well and a finite quasiparticle lifetime. Boundary conditions are chosen to comply with the charge neutrality condition. This model provides a fair description of experimental results in ultrathin lead films: on average, the superconducting gap decreases with thickness and it is always below the bulk value. Clear oscillations, remnants of the shape resonances, are still observed for intermediate thicknesses. For materials with a weaker electron-phonon coupling and negligible disorder, a modest enhancement of superconductivity seems to be feasible. The relaxation of the charge neutrality condition, which is in principle justified in complex oxide heterostructures and other materials, would lead to a much stronger enhancement of superconductivity by size effects.

Romero-Bermdez, Aurelio; Garca-Garca, Antonio M.

2014-02-01

266

Stress induced deformations of thin silicon dioxide films  

Microsoft Academic Search

Residual compressive stresses are commonplace in semiconductor processing and are a leading cause of deformation and delamination of thin films. The principles of stress-induced mechanical deformation can be harnessed to produce controllable changes in the morphology of thin films. For this thesis work, deformations of thin silicon dioxide films which result from the compressive stress in the films have been

Justin Raymond Serrano

2004-01-01

267

LPG sensing performance of nanostructured zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Nanostructured zinc oxide thin films were prepared using ultrasonic spray pyrolysis technique. Zinc acetate was used as a starting precursor. As prepared thin films were characterized using different analytical techniques. The sensing performance of the nanostructured zinc oxide thin films was studied on exposure of various gases. The films were observed to be most sensitive (S= 1727) to LPG at 300C.

Bari, A. R.; Patil, L. A.

2013-06-01

268

Evidence for spin mixing in holmium thin film and crystal samples  

NASA Astrophysics Data System (ADS)

In a number of recent experiments, holmium has been shown to promote spin-triplet pairing when in proximity to a spin-singlet superconductor. The condition for the support of spin-triplet pairing is that the ferromagnet should have an inhomogeneous magnetic state at the interface with the superconductor. Here we use Andreev reflection spectroscopy to study the properties of single ferromagnet/superconductor interfaces formed of holmium and niobium, as a function of the contact resistance of the junction between them. We find that both single-crystal and c-axis-oriented thin-film holmium show unusual behavior for low junction contact resistance, characteristic of spin-mixing-type properties, which are thought necessary to underpin spin-triplet formation. We also explore whether this signature is observed when the junction is formed of Ni0.19Pd0.81 and niobium.

Usman, I. T. M.; Yates, K. A.; Moore, J. D.; Morrison, K.; Pecharsky, V. K.; Gschneidner, K. A.; Verhagen, T.; Aarts, J.; Zverev, V. I.; Robinson, J. W. A.; Witt, J. D. S.; Blamire, M. G.; Cohen, L. F.

2011-04-01

269

Magnetostrictive thin films prepared by RF sputtering  

NASA Astrophysics Data System (ADS)

Fe 80B 20 thin films have been prepared by ion beam sputtering magnetron on room temperature. The films were fabricated on different substrates to compare the different magnetic and structural properties. In particular the growth of films on flexible substrates (PDMS, Kapton) has been studied to allow a simple integration of the system in miniaturized magnetostrictive devices. X-ray diffraction patterns indicate that films are mainly amorphous although the presence of some Fe nanoparticles cannot be ruled out. The coercive field of thin films ranges between 15 and 35 Oe, depending on substrate. Magnetostriction measurements indicate the strong dependence of the saturation magnetostriction with the substrate. Samples on flexible substrates exhibit a better performance than samples deposited onto glass substrates.

Carabias, I.; Martinez, A.; Garcia, M. A.; Pina, E.; Gonzalez, J. M.; Hernando, A.; Crespo, P.

2005-04-01

270

AC impedance analysis of polypyrrole thin films  

NASA Technical Reports Server (NTRS)

The AC impedance spectra of thin polypyrrole films were obtained at open circuit potentials from -0.4 to 0.4 V vs SCE. Two limiting cases are discussed for which simplified equivalent circuits are applicable. At very positive potentials, the predominantly nonfaradaic AC impedance of polypyrrole is very similar to that observed previously for finite porous metallic films. Modeling of the data with the appropriate equivalent circuit permits effective pore diameter and pore number densities of the oxidized film to be estimated. At potentials from -0.4 to -0.3 V, the polypyrrole film is essentially nonelectronically conductive and diffusion of polymer oxidized sites with their associated counterions can be assumed to be linear from the film/substrate electrode interface. The equivalent circuit for the polypyrrole film at these potentials is that previously described for metal oxide, lithium intercalation thin films. Using this model, counterion diffusion coefficients are determined for both semi-infinite and finite diffusion domains. In addition, the limiting low frequency resistance and capacitance of the polypyrrole thin fims was determined and compared to that obtained previously for thicker films of the polymer. The origin of the observed potential dependence of these low frequency circuit components is discussed.

Penner, Reginald M.; Martin, Charles R.

1987-01-01

271

Solvothermal annealing of block copolymer thin films.  

PubMed

A two-stage annealing process for block copolymer films was introduced consisting of a solvent vapor exposure followed by a thermal cycle. By heating the film but not the chamber, changes in the ambient vapor pressure of the solvent were avoided. Films of block copolymers and homopolymers showed transient nonmonotonic swelling behavior immediately after solvent exposure that was dependent on how the thin film was cast before the anneal. Thermal cycling of the solvent-swelled block copolymer films during the solvent vapor anneal (SVA) caused the films to deswell in 1-10 s and produced well-ordered microdomains in templated 45.5 and 51.5 kg/mol polystyrene-block-polydimethylsiloxane films annealed in toluene and n-heptane vapors for total process times of 30 s to 5 min. PMID:24083573

Gotrik, Kevin W; Ross, C A

2013-11-13

272

Mirrorlike pulsed laser deposited tungsten thin film  

SciTech Connect

Mirrorlike tungsten thin films on stainless steel substrate deposited via pulsed laser deposition technique in vacuum (10{sup -5} Torr) is reported, which may find direct application as first mirror in fusion devices. The crystal structure of tungsten film is analyzed using x-ray diffraction pattern, surface morphology of the tungsten films is studied with scanning electron microscope and atomic force microscope. The film composition is identified using energy dispersive x-ray. The specular and diffuse reflectivities with respect to stainless steel substrate of the tungsten films are recorded with FTIR spectra. The thickness and the optical quality of pulsed laser deposition deposited films are tested via interferometric technique. The reflectivity is approaching about that of the bulk for the tungsten film of thickness {approx}782 nm.

Mostako, A. T. T.; Khare, Alika [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Rao, C. V. S. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2011-01-15

273

Sequentially evaporated thin film YBa2Cu3O(7-x) superconducting microwave ring resonator  

NASA Technical Reports Server (NTRS)

There is great interest in the application of thin film high temperature superconductors in high frequency electronic circuits. A ring resonator provides a good test vehicle for assessing the microwave losses in the superconductor and for comparing films made by different techniques. Ring resonators made of YBa2Cu3O(7-x) have been investigated on LaAlO3 substrates. The superconducting thin films were deposited by sequential electron beam evaporation of Cu, Y, and BaF2 with a post anneal. Patterning of the superconducting film was done using negative photolithography. A ring resonator was also fabricated from a thin gold film as a control. Both resonators had a gold ground plane on the backside of the substrate. The ring resonators' reflection coefficients were measured as a function of frequency from 33 to 37 GHz at temperatures ranging from 20 K to 68 K. The resonator exhibited two resonances which were at 34.5 and 35.7 GHz at 68 K. The resonant frequencies increased with decreasing temperature. The magnitude of the reflection coefficients was in the calculation of the unloaded Q-values. The performance of the evaporated and gold resonator are compared with the performance of a laser ablated YBa2Cu3O(7-x) resonator. The causes of the double resonance are discussed.

Rohrer, Norman J.; To, Hing Y.; Valco, George J.; Bhasin, Kul B.; Chorey, Chris; Warner, Joseph D.

1990-01-01

274

High temperature superconductor resistive switch characteristics  

Microsoft Academic Search

High Temperature Superconductor (HTSc) will switch from the superconducting state to the normal resistive state when an intrinsic critical current density is exceeded. We have measured the transition characteristics for HTSc thin films forced into transition by the application of voltage driven overcurrents. These thin films were used in the development of prototype HTSc fault current limiting devices. The prototype

T. J. Scholz; John P. Barber

1997-01-01

275

Thin film dielectric composite materials  

DOEpatents

A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

Jia, Quanxi (Los Alamos, NM) [Los Alamos, NM; Gibbons, Brady J. (Los Alamos, NM) [Los Alamos, NM; Findikoglu, Alp T. (Los Alamos, NM) [Los Alamos, NM; Park, Bae Ho (Los Alamos, NM) [Los Alamos, NM

2002-01-01

276

Thermal nitridation of silicon dioxide thin films on silicon  

Microsoft Academic Search

Silicon oxynitride thin films were examined as possible VLSI MISFET gate dielectrics. Thermally grown silicon dioxide thin films on silicon were nitrided in 1 atm NH at 1150°C for various times between 10 and 240 minutes. The films were between 120 and 1630 A thick. Chemical kinetics severely limited the incorporation of nitrogen into the film; only the thinnest films

Koba

1986-01-01

277

Synthesis and characterization of multiferroic thin films  

NASA Astrophysics Data System (ADS)

Multiferroic materials and multiferroic materials systems which simultaneously exhibit ferroelectricity and magnetism have attracted great attention because of their exotic physical properties and their potential applications which utilize coupling of magnetism and ferroelectricity. The goal of this thesis was to study multiferroic materials systems in thin film and multilayer forms in order to explore the possibility of fabricating room temperature thin film devices. In particular, we have focused on two types of multiferroic materials systems: (1) intrinsic multiferroic/magnetoelectric thin film materials and (2) magnetostrictive/piezoelectric bilayer systems for investigation of the strain-mediated magnetoelectric (ME) effect. BiFeO3 is an intrinsic multiferroic which displays ferroelectricity and antiferromagnetism at room temperature, and thus of strong interest for ambient device applications. In this thesis, we have extensively investigated the role of microstructure on the properties of BiFeO3 thin films. We studied multiphase formation in Bi-Fe-O thin films, and found that formation of secondary phases such as alpha-Fe2O3, gamma-Fe 2O3, and Fe3O4 increased overall saturation magnetization and released the misfit strain of the BiFeO3 grains in the films. We also observed large polarization in Bi-Fe-O thin films containing secondary phases that have almost fully relaxed the misfit strain. We have studied several aspects of the ME effect which are directly relevant to possible novel device applications. Electric field tunable spintronic devices using the ME effect have been proposed. In one such device configuration, the desired effect is electric field tuning of giant magnetoresistance or tunnel magnetoresistance through control of exchange bias via the ME effect. We have investigated the feasibility of such a device using exchange-biased Co/Pt multilayers on Cr2O3 thin films. The strain-mediated ME effect at the interface of magnetostrictive/ piezoelectric bilayers has been widely used to demonstrate magnetic field detection with extremely high sensitivity. Although the overall mechanism of such an effect is known, the details of the bilayer interfaces and how they affect the coupling is not understood. In order to directly observe the strain-mediated ME coupling effect, we fabricated bilayer thin film structures and performed in-situ dynamic observation of magnetic domains while an electric-field was being applied using Lorentz transmission electron microscopy. Electric-field induced motion of magnetic domain boundaries in the magnetostrictive layer was observed for the first time.

Lim, Sung Hwan

278

All thin film magnetoelectric magnetic field sensors.  

NASA Astrophysics Data System (ADS)

We have fabricated prototype ac magnetic field sensors operating at room temperature based on all thin film ME devices showing strong magnetoelectric (ME) coupling. The ME layers consist of a sol-gel derived Pb(Zr0.52Ti0.48)TiO3 (PZT) film and a dc magnetron sputter deposited magnetostrictive Fe70Ga30 (FeGa) film. The bilayer structures are prepared on micromachined Si wafers, and the laser cutting technique is used to release and isolate the cantilevers for optimization of the sensor performance. The PZT layer and the FeGa layer couple via the piezoelectric d31 mode and the corresponding ME coupling coefficient is as high as 2 V/(Oe cm) for a lateral dimension of 1 mm^2 device at the mechanical resonant frequency of 333 Hz of a Si cantilever. The soft magnetic FeGa film requires dc bias magnetic field of around 90 Oe to operate the thin film ME device. The coupling between the PZT and the FeGa films is remarkably improved by depositing a 40 nm thick Pt intermediate layer. The clamping effect on the ME coupling is dramatically reduced by back-etching the Si cantilever down to 35 ?m thick. The present work indicates presence of robust ME coupling in microfabricated multilayer thin film ME devices.

Zhao, Peng

2009-03-01

279

Capillary stress in microporous thin films  

SciTech Connect

Development of capillary stress in porous xerogels, although ubiquitous, has not been systematically studied. The authors have used the beam bending technique to measure stress isotherms of microporous thin films prepared by a sol-gel route. The thin films were prepared on deformable silicon substrates which were then placed in a vacuum system. The automated measurement was carried out by monitoring the deflection of a laser reflected off the substrate while changing the overlying relative pressure of various solvents. The magnitude of the macroscopic bending stress was found to reach a value of 180 MPa at a relative pressure of methanol, P/Po = 0.001. The observed stress is determined by the pore size distribution and is an order of magnitude smaller in mesoporous thin films. Density Functional Theory (DFT) indicates that for the microporous materials, the stress at saturation is compressive and drops as the relative pressure is reduced.

Samuel, J.; Hurd, A.J.; Frink, L.J.D.; Swol, F. van [Sandia National Labs., Albuquerque, NM (United States); Brinker, C.J. [Sandia National Labs., Albuquerque, NM (United States). Ceramic Processing Science Dept.]|[Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineering Ceramics; Raman, N.K. [Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineered Ceramics

1996-06-01

280

Method for synthesizing thin film electrodes  

DOEpatents

A method for making a thin-film electrode, either an anode or a cathode, by preparing a precursor solution using an alkoxide reactant, depositing multiple thin film layers with each layer approximately 500 1000 .ANG. in thickness, and heating the layers to above 600.degree. C. to achieve a material with electrochemical properties suitable for use in a thin film battery. The preparation of the anode precursor solution uses Sn(OCH.sub.2C(CH.sub.3).sub.3).sub.2 dissolved in a solvent in the presence of HO.sub.2CCH.sub.3 and the cathode precursor solution is formed by dissolving a mixture of (Li(OCH.sub.2C(CH.sub.3).sub.3)).sub.8 and Co(O.sub.2CCH.sub.3).H.sub.2O in at least one polar solvent.

Boyle, Timothy J. (Albuquerque, NM)

2007-03-13

281

Mesoscale morphologies in polymer thin films.  

SciTech Connect

In the midst of an exciting era of polymer nanoscience, where the development of materials and understanding of properties at the nanoscale remain a major R&D endeavor, there are several exciting phenomena that have been reported at the mesoscale (approximately an order of magnitude larger than the nanoscale). In this review article, we focus on mesoscale morphologies in polymer thin films from the viewpoint of origination of structure formation, structure development and the interaction forces that govern these morphologies. Mesoscale morphologies, including dendrites, holes, spherulites, fractals and honeycomb structures have been observed in thin films of homopolymer, copolymer, blends and composites. Following a largely phenomenological level of description, we review the kinetic and thermodynamic aspects of mesostructure formation outlining some of the key mechanisms at play. We also discuss various strategies to direct, limit, or inhibit the appearance of mesostructures in polymer thin films as well as an outlook toward potential areas of growth in this field of research.

Ramanathan, M.; Darling, S. B. (Center for Nanoscale Materials)

2011-06-01

282

Thin film oxygen partial pressure sensor  

NASA Technical Reports Server (NTRS)

The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

1972-01-01

283

Overturning Droplets in Thin Fluid Films  

Microsoft Academic Search

Abstract Overturning,Droplets in Thin Fluid Films by Anand,Patil May 2001 We investigate the formation,of droplets in a thin liquid lm,on a solid substrate due to the combined,action of surface tension and van der Waals forces. Current models,for droplet formation,assume,that droplets have a shallow,prole. By re- moving that assumption and numerically solving for stable droplet proles, we have modelled,droplets that separate

Anand Patil; Andrew Bernoff

284

Emittance theory for thin film selective emitter  

NASA Technical Reports Server (NTRS)

Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

1994-01-01

285

Fast, precise, tomographic measurements of thin films  

SciTech Connect

The authors describe a nondestructive measurement method that enables them to obtain the cross-sectional thickness profile of thin-film layers fast with a single operation of measurement. The method is based on spectrally resolved white-light interferometry, being capable of reconstructing the tomographic height map of thin films with depth resolutions in the nanometer range. In terms of the measuring speed and resolution, the proposed method is well suited for the in-line high-speed inspection of microelectronics devices produced in large quantities particularly in the semiconductors and flat panel displays industries.

Ghim, Young-Sik; Kim, Seung-Woo [Billionth Uncertainty Precision Engineering Group, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Science Town, Daejeon 305-701(Korea, Republic of)

2007-08-27

286

Micro-sensor thin-film anemometer  

NASA Technical Reports Server (NTRS)

A device for measuring turbulence in high-speed flows is provided which includes a micro-sensor thin-film probe. The probe is formed from a single crystal of aluminum oxide having a 14.degree. half-wedge shaped portion. The tip of the half-wedge is rounded and has a thin-film sensor attached along the stagnation line. The bottom surface of the half-wedge is tilted upward to relieve shock induced disturbances created by the curved tip of the half-wedge. The sensor is applied using a microphotolithography technique.

Sheplak, Mark (Inventor); McGinley, Catherine B. (Inventor); Spina, Eric F. (Inventor); Stephens, Ralph M. (Inventor); Hopson, Jr., Purnell (Inventor); Cruz, Vincent B. (Inventor)

1996-01-01

287

Feasibility Study of Thin Film Thermocouple Piles  

NASA Technical Reports Server (NTRS)

Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

Sisk, R. C.

2001-01-01

288

Superconducting thin films on potassium tantalate substrates  

DOEpatents

A superconductive system for the lossless transmission of electrical current comprising a thin film of superconducting material Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x epitaxially deposited upon a KTaO.sub.3 substrate. The KTaO.sub.3 is an improved substrate over those of the prior art since the it exhibits small lattice constant mismatch and does not chemically react with the superconducting film.

Feenstra, Roeland (Oak Ridge, TN); Boatner, Lynn A. (Oak Ridge, TN)

1992-01-01

289

Heterogeneous Thin Films of Martensitic Materials  

Microsoft Academic Search

:We study the effective behavior of heterogeneous thin films with three competing length scales: the film thickness and the\\u000a length scales of heterogeneity and material microstructure. We start with three-dimensional nonhomogeneous nonlinear elasticity\\u000a enhanced with an interfacial energy of the van der Waals type, and derive the effective energy density as all length scales\\u000a tend to zero with given limiting

Y. C. Shu

2000-01-01

290

Thin film effects in ultrasonic wafer thermometry  

Microsoft Academic Search

We use an ultrasonic technique where the temperature dependence of lowest order anti-symmetric Lamb wave velocity in the silicon wafer is utilized for in-situ temperature measurement in the 20-1000C range. In almost all wafer processing steps, one or more layers of thin films are present on the wafers. The effects of these films on temperature sensitivity is investigated. A theoretical

F. L. Degertekin; J. Pei; B. V. Honein; B. T. Khuri-Yakub; K. C. Saraswat

1994-01-01

291

Study of obliquely deposited thin cobalt films  

Microsoft Academic Search

Thin cobalt films, 40nm and 100nm in thickness, were deposited by thermal evaporation at an incidence angle of 45 in a system with a base pressure of approximately 10?5mbar, simultaneously on unheated glass substrates and NaCl crystals. The magnetic microstructure of the films was investigated with the conventional Bitter pattern technique and the Fresnel mode of transmission electron microscopy (TEM),

W. Szmaja; W. Koz?owski; J. Balcerski; P. J. Kowalczyk; J. Grobelny; M. Cichomski

2010-01-01

292

Ionic implantation in scandium diphthalocyanine thin films  

Microsoft Academic Search

Ionic implantations have been carried out in amorphous scandium diphthalocyanine thin films in order to get n- and p-doping and to make elementary electronic devices like p-n junctions. Absorption spectroscopy has been used to define implantation conditions which would not involve too much damage in the films. Thermoelectric power measurements show that the samples (initially p-type) become generally n-type after

S. Robinet; M. Salvi; C. Clarisse

1991-01-01

293

Thin ferroelectric films for thermal detector applications  

Microsoft Academic Search

The deposition of thin films of lead scandium tantalate (Pb(Sc1\\/2Ta1\\/2O3) have been investigated by two processing routes. In the first, progress is reviewed for chemical vapour deposition in a purpose built low pressure reactor, utilising suitable modified proprietary precursors. Deposition has been studied over the temperature range 400800C and, in general, amorphous films result which convert to crystalline perovskites on

F. Ainger; A. Patel; N. M. Shorrocks; C. Trundle; R. W. Whatmore

1992-01-01

294

Annealed CVD molybdenum thin film surface  

DOEpatents

Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.

Carver, Gary E. (Tucson, AZ); Seraphin, Bernhard O. (Tucson, AZ)

1984-01-01

295

Thin Films in the Technology of Superhigh Frequencies.  

National Technical Information Service (NTIS)

A comprehensive discussion of the physics, manufacturing processes and applications of thin films in modern communications technology. The following subjects are discussed in detail: (1) Structure and properties of thin films: vacuum vaporization, cathode...

1971-01-01

296

Semiconducting Thin Films: An Annotated Bibliography, 1967 Supplement.  

National Technical Information Service (NTIS)

The 1967 supplement to NOLC Report 712, Semiconducting Thin Films, An Annotated Bibliography (1956-1966) (AD-655 100) continues the comprehensive bibliographic survey on the preparation, properties, applications, and theory of semiconducting thin films. I...

W. R. Turnbull

1968-01-01

297

Current Oscillations in Doped Thin Films of CdSe.  

National Technical Information Service (NTIS)

The previously unreported phenomenon of current oscillations in doped thin films of cadmium selenide was explored. It was concluded that, with appropriate processing, devices made with thin films of CdSe will exhibit current oscillations when high electri...

J. J. Symanski

1969-01-01

298

Thermally induced transitions in polymer thin films  

NASA Astrophysics Data System (ADS)

Polymers, by virtue of their chemical composition and molecular architecture, exhibit a diverse range of microstructural features and properties. As thin films, due primarily to effects associated with confinement and interfacial interactions, their properties may be film-thickness dependent. The significance of their thickness-dependent behavior is underscored by the fact that polymer films are of technological interest in areas that include, sensors, catalysts and organic electronics. One challenge associated with the use of thin film polymers is to understand the role of confinement and interfacial interactions on thermally induced transitions, such as vitrification and various morphological transitions. To this end, the work presented in this dissertation focuses on the behavior of thermally induced transitions in two thin film polymer-based systems: (1) an A-b-B diblock copolymer which can undergo a disorder-to-order transitions (ODT), wherein the ordered state exhibits varying geometrical symmetries, depending on the relative volume fractions of the A and B components; (2) an amorphous polymer filled with particles of nanoscale dimensions. The first of three problems examined is the influence of supercritical carbon dioxide (scCO2) on the order-disorder transition of thin film symmetric A-b-B diblock copolymer systems. We show that the transition (chiN)ODT, where chi is the energetic A-B Flory-Huggins interaction parameter and N is the total degree of polymerization of the copolymer, of the thin film decreased 20% compared to the bulk; the decrease was more significant in scCO2 environments. The decrease of (chiN) ODT in scCO2 is contrary to observations in bulk copolymer-scCO 2 systems where the effective A-B interactions are weaker, hence the condition for the transition increases to higher (chiN)ODT values. With regard to the second problem, we show for the first time experimentally that nanoparticles induced order into thin films of a symmetric A-b-B diblock copolymer at temperatures below the bulk ODT. Finally, we examine the influence of polystyrene (PS) grafted nanoparticles on the glass transition of PS films of varying molecular weight and thickness. We demonstrate that by controlling spatial distribution of nanoparticles, through driving forces of entropic origin, the glass transition temperature of the film can be changed drastically, as much as tens of degrees.

Arceo, Abraham

299

Kinematic and dynamic vortices in a thin film driven by an applied current and magnetic field  

NASA Astrophysics Data System (ADS)

Using a Ginzburg-Landau model, we study the vortex behavior of a rectangular thin film superconductor subjected to an applied current fed into a portion of the sides and an applied magnetic field directed orthogonal to the film. Through a center manifold reduction we develop a rigorous bifurcation theory for the appearance of periodic solutions in certain parameter regimes near the normal state. The leading order dynamics yield in particular a motion law for kinematic vortices moving up and down the center line of the sample. We also present computations that reveal the co-existence and periodic evolution of kinematic and magnetic vortices.

Peres Hari, Lydia; Rubinstein, Jacob; Sternberg, Peter

2013-10-01

300

Microwave complex conductivity of the YBCO thin films as a function of static external magnetic field  

NASA Astrophysics Data System (ADS)

A sapphire rod resonator operating at microwave frequencies was used to determine the electric properties of 600 nm thick YBCO films in the superconducting state. The rigorous electromagnetic modelling was applied to transform the measured Q-factor and the resonant frequency to the complex conductivity of high accuracy, which was previously shown to describe the intrinsic properties of superconductor thin films in more precise manner than the complex impedance. Static external magnetic field induces typical transition to normal state due to introduction of magnetic vortices into the sample. Observed magnetic hysteresis has the origin in the strong temperature dependent pinning. Additional energy absorption at about 1.5 T was observed.

Krupka, J.; Judek, J.; Jastrzebski, C.; Ciuk, T.; Wosik, J.; Zdrojek, M.

2014-03-01

301

Optimization of YBa sub 2 Cu sub 3 O sub 7 thin films for multilayers  

SciTech Connect

This paper studies the in situ growth of YBa{sub 2}Cu{sub 3}O{sub 7} thin films using e-beam coevaporation. The growth conditions for smooth YBa{sub 2}Cu{sub 3}O{sub 7} films with high T{sub c} and J{sub c} have been established. Superconductor-insulator and SIS structures have been grown using Y{sub 2}O{sub 3} as an epitaxial insulator, and preliminary vertical transport measurements in patterned structures are reported.

Humphreys, R.G.; Chew, N.G.; Satchell, J.S.; Goodyear, S.W.; Edwards, J.A.; Blenkinsop, S.E. (Royal Signals and Radar Establishment, Malvern (United Kingdom))

1991-03-01

302

Sol-gel derived ?-BBO thin film  

NASA Astrophysics Data System (ADS)

(beta) -BaB2O4((beta) -BBO) is known as one of the best inorganic nonlinear crystals. It is now widely used for frequency doubling, frequency mixing in the UV range and optical parametric oscillation in the UV and near infrared regions. To put this material into thin film form would make it very attractive for integrated optical devices. Vacuum deposition techniques are not suitable for the fabrication of borates thin films due to the difficult evaporation or sputtering of oxides based on light elements. The low processing temperature of the sol-gel method allows the formation of stoichiometric and expected oxygen coordination of BaB2O4 in liquid phase. (beta) -BBO thin films has been successfully prepared by the sol-gel method through hydrolysis of barium and boron alkoxides. The accomplishment of hydrolysis is found to be essential for the removal of residual organic at high temperatures. The choice of precursors, hydrolysis ratio, and thermal treatments have critical influences on the formation, the morphology and the nucleation of (beta) -BBO phase of the film. The undesirable interaction between the film and the substrate limits the formation of (beta) -BBO polycrystalline film to only a few selected substrates.

Nie, Wenjiang; Lurin, Christian L.; Paz-Pujalt, Gustavo R.

1992-12-01

303

Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films  

SciTech Connect

OAK B204 Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films. The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and hTi-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials.

Hellman, Frances

1998-10-03

304

Physical properties in thin films of iron oxides  

Microsoft Academic Search

We have grown hematite (?-Fe2O3) thin films on stainless steel substrates and magnetite (Fe3O4) thin films on (001)-Si single crystal substrates by a RF magnetron sputtering process. ?-Fe2O3 thin films were grown in an Ar atmosphere at substrate temperatures around 400?C, and Fe3O4 thin films in an Ar\\/O2 reactive atmosphere at substrate temperatures around 500?C. Conversion electron Mssbauer (CEM) spectra

J. D. Uribe; J. Osorio; C. A. Barrero; D. Girataa; A. L. Morales; A. Hoffmann

2008-01-01

305

Properties of thin LPCVD silicon oxynitride films  

NASA Astrophysics Data System (ADS)

Thin, uniform silicon oxynitride films with films thicknesses of ? 10 nm were successfully deposited by low pressure chemical vapor deposition (LPCVD). The reactant gases were SiH2Cl2, N2O, and NH3. The compositional uniformity of these films as a function of depth was good. The structure of these oxynitride films was found to be dominated by the mixed matrix of Si, N, and 0, rather than a physical mixture of SiO2 and Si3N4 clusters. N-H bonding was observed and the total amount of hydrogen in the as-deposited film was on the order of 5 x l020/cm3. No H-OH or Si-OH bonds were detected. Excellent dielectric breakdown distributions were found for oxynitride films with equivalent oxide film thicknesses as low as 7.5 nm. The conduction of Si-N-0 films depended on film composition. A small capacitor-voltage (C-V) window (< 0.1 V) was observed for the Si-N-O/Si structures. The midgap surface state density was on the order of 5 x 1010/cm2 /eV. Either trapping of holes or the generation of positive states were found after high field stressing of the oxynitride films.

Pan, P.; Abernathey, J.; Schaefer, C.

1985-09-01

306

History dependence of the magnetization of thin HTSC films: An explanation for distorted SQUID signals  

NASA Astrophysics Data System (ADS)

The magnetizations of thin film disk-shaped type-II superconductors in perpendicular magnetic fields are considered by aid of Mikheenko's critical state model which has been corrected by Zhu for the case of a time-varying periodic field. This paper presents the application of this scheme to an arbitrary nonperiodic time dependence H( t). We calculate the influence of field inhomogeneities in a magnetometer on the current density distribution of a disk-shaped type-II superconductor. The resulting SQUID pickup signals and magnetic moments are compared to measurements performed on a 200 nm thick YBa 2Cu 3O 7 film in the irreversible regime of the phase diagram. Theory and experiment show good agreement, even for heavily distorted SQUID signals.

Wienss, A.; Jakob, G.; Voss-de Haan, P.; Adrian, H.

1997-02-01

307

Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films  

NASA Technical Reports Server (NTRS)

Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation forces, e.g. microgravity - magnetic damping devices.

Schoenhuber, P.; Moon, F. C.

1995-01-01

308

Biaxial Fatigue Testing of Thin Films  

SciTech Connect

A new experimental setup, which allows for testing in an equi-biaxial loading condition, has been developed and applied to investigate the fatigue behaviour of thin films. A load controlled cycling, performed at room temperature on flat specimens, reproduces the strain amplitude and mean strain in the film corresponding to a thermal cycling in a given temperature range. The setup is based on the ring-on-ring test, which has been successfully used in biaxial fracture testing of glass and ceramics, and includes an optical in-situ failure detection system. The method is validated for specimens consisting in a gold film deposited on a polymer substrate.

Eve, S.; Huber, N.; Ernst, E.; Kraff, O. [Institut fuer Materialforschung II, Forschungszentrum Karlsruhe GmbH, Postfach 36 40, 76021 Karlsruhe (Germany); Last, A.; Schlagenhof, M. [Institut fuer Mikrostrukturtechnik, Forschungszentrum Karlsruhe GmbH, Postfach 36 40, 76021 Karlsruhe (Germany)

2006-02-07

309

Growth modes of nanoparticle superlattice thin films  

NASA Astrophysics Data System (ADS)

We report on the fabrication and characterization of iron oxide nanoparticle thin film superlattices. The formation into different film morphologies is controlled by tuning the particle plus solvent-to-substrate interaction. It turns out that the wetting vs dewetting properties of the solvent before the self-assembly process during solvent evaporation plays a major role in determining the resulting film morphology. In addition to layerwise growth three-dimensional mesocrystalline growth is also evidenced. The understanding of the mechanisms ruling nanoparticle self-assembly represents an important step towards the fabrication of novel materials with tailored optical, magnetic or electrical transport properties.

Mishra, D.; Greving, D.; Badini Confalonieri, G. A.; Perlich, J.; Toperverg, B. P.; Zabel, H.; Petracic, O.

2014-05-01

310

Growth modes of nanoparticle superlattice thin films.  

PubMed

We report on the fabrication and characterization of iron oxide nanoparticle thin film superlattices. The formation into different film morphologies is controlled by tuning the particle plus solvent-to-substrate interaction. It turns out that the wetting vs dewetting properties of the solvent before the self-assembly process during solvent evaporation plays a major role in determining the resulting film morphology. In addition to layerwise growth three-dimensional mesocrystalline growth is also evidenced. The understanding of the mechanisms ruling nanoparticle self-assembly represents an important step towards the fabrication of novel materials with tailored optical, magnetic or electrical transport properties. PMID:24785547

Mishra, D; Greving, D; Badini Confalonieri, G A; Perlich, J; Toperverg, B P; Zabel, H; Petracic, O

2014-05-23

311

Photointercalation characteristics of thin WO3 films  

NASA Astrophysics Data System (ADS)

Photoinduced proton injection properties of amorphous thin WO3 films have been studied for a cell of the form quartz glass/semitransparent Au/ethanol/WO3/indium-tin-oxide-coated glass. When the cell was illuminated with near-uv light through a quartz window under open circuit conditions, a definite reversible change was induced in the optical and electrical properties of WO3 films. On the basis of some experimental analyses, this effect is attributed to photointercalation (PI) of protons into WO3 films. It is also demonstrated that WO3-based PI cells efficiently operate as an erasable device for storage and modulation of optical information.

Nagasu, Masahiro; Koshida, Nobuyoshi

1992-01-01

312

Photointercalation effect of thin WO3 films  

NASA Astrophysics Data System (ADS)

It is shown that thin amorphous films of WO3 exhibit a photoinduced reversible coloration in an electrochemical cell of the form quartz/semitransparent Au/ethanol/WO3/In2O3-coated glass. From measurements of the optical and electrical properties of the films, the coloration is attributed to the formation of HxWO3, presumably due to a photointercalation of protons into WO3 films. This effect is potentially useful for storage, learning, and modulation of two-dimensional optical information.

Nagasu, Masahiro; Koshida, Nobuyoshi

1990-09-01

313

Photoluminescence studies on RF plasma-polymerized thin films  

Microsoft Academic Search

Conjugated polymers in the form of thin films play an important role in the field of materials science due to their interesting properties. Polymer thin films find extensive applications in the fabrication of devices, such as light emitting devices, rechargeable batteries, super capacitors, and are used as intermetallic dielectrics and EMI shieldings. Polymer thin films prepared by plasma-polymerization are highly

S. Saravanan; C. Joseph Mathai; M. R. Anantharaman; S. Venkatachalam; D. K. Avasthi; F. Singh

2005-01-01

314

Study on the Ferroelectric Thin Films for Uncooled Infrared Detection  

Microsoft Academic Search

Some results on the microstructure controlling and characterization of ferroelectric thin films for uncooled infrared detections are presented. Several novel technologies have been developed to control the microstructures, e.g., grain size, grain shape, and the texture of BST, PZT thin films as well as to fabricate PZT thin films at low temperature. 256 1 pixels infrared detector has been

Junhao Chu; Xiangjian Meng

2007-01-01

315

Semiconductor cooling by thin-film thermocouples  

NASA Technical Reports Server (NTRS)

Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

Tick, P. A.; Vilcans, J.

1970-01-01

316

Studies of Electron Scattering in Thin Films.  

National Technical Information Service (NTIS)

Several series of experiments were performed to establish the mechanism of current flow in vacuum deposited Au-MgO-Au thin film sandwich devices in which each layer was deposited from a high purity source by electron beam evaporation. The mechanism of inj...

D. E. Speliotis

1969-01-01

317

Optical Thin Film Monitoring Using Optical Fibers.  

National Technical Information Service (NTIS)

A technique for monitoring optical thin film thickness by direct evaporation onto the end of an optical fiber is described. The optical fiber is suspended inside a coating chamber so that the fiber distal end faces the evaporation source and is illuminate...

N. L. Thomas

1986-01-01

318

Thermal fatigue testing of thin metal films  

Microsoft Academic Search

An experimental method is described for performing thermal fatigue testing of thin films and lines on substrates. The method uses Joule heating from alternating currents to generate temperature, strain, and stress cycles in the metal structures. The apparatus has been installed in a scanning electron microscope and allows in situ observations of the fatigue damage evolution. First observations on Cu

R. R. Keller; C. A. Volkert

2004-01-01

319

Thin-Film Solid Oxide Fuel Cells  

NASA Technical Reports Server (NTRS)

The development of thin-film solid oxide fuel cells (TFSOFCs) and a method of fabricating them have progressed to the prototype stage. This can result in the reduction of mass, volume, and the cost of materials for a given power level.

Chen, Xin; Wu, Nai-Juan; Ignatiev, Alex

2009-01-01

320

Stable Localized Patterns in Thin Liquid Films.  

National Technical Information Service (NTIS)

We study a 2-D nonlinear evolution equation which describes the 3-D spatiotemporal behavior of the air-liquid interface of a thin liquid film lying on the underside of a cooled horizontal plate. We show that the Marangoni effect can stabilize the destabil...

R. J. Deissler A. Oron

1991-01-01

321

Spreading Profiles of Molecularly Thin Perfluoropolyether Films  

Microsoft Academic Search

Perfluoropolyethers (PFPEs) are widely used as lubricants on magnetic recording media. The mobility of the PFPE on the protective carbon overcoat of the media is widely accepted to be intimately coupled to the resulting tribological performance. The flow properties of molecularly thin films of nonpolar PFPEZ and polar PFPE Zdol fractions on solid surfaces were investigated by measuring the spreading

G. W. Tyndall; T. E. Karis; M. S. Jhon

1999-01-01

322

Adhesion and Thin-Film Module Reliability.  

National Technical Information Service (NTIS)

Among the infrequently measured but essential properties for thin-film (T-F) module reliability are the interlayer adhesion and cohesion within a layer. These can be cell contact layers to glass, contact layers to the semiconductor, encapsulant to cell, g...

G. J. Jorgensen T. J. McMahon

2006-01-01

323

Fracture of nanoporous thin-film glasses  

Microsoft Academic Search

Fracture of nanoporous thin-film glasses is a significant challenge for the integration of these mechanically fragile materials in emerging microelectronic and biological technologies. In particular, the integration of these materials has been limited by accelerated cracking rates in moist environments leading to premature failure. Here, we demonstrate how cracking is affected by aqueous solution chemistry, and reveal anomalously high crack-growth

Eric P. Guyer; Reinhold H. Dauskardt

2003-01-01

324

Low temperature OMCVD of thin rhodium films.  

National Technical Information Service (NTIS)

Thin, highly reflective rhodium films with metal compositions greater than 98% (elemental weight percentage) have been deposited by chemical vapor deposition using Rh(allyl)(sub 3) (allyl = (eta)(sup 3)-C(sub 3)H(sub 5)) in the presence of a hydrogen plas...

J. R. Laia A. P. Sattelberger D. C. Smith J. C. DeSantis

1992-01-01

325

Spray deposition of biomolecular thin films  

Microsoft Academic Search

In this paper, a parametric study of the airbrush deposition technique was investigated for the deposition biomolecular thin films. The airbrush parameters under investigation were intake valve opening, carrier gas pressure, distance between the airbrush and substrate, concentration of solution, vapor pressure of solvent, and hydrophobic\\/hydrophilic substrate surface. This study was assessed through the characterization of dried droplet residues of

Mihir K Rayan

2008-01-01

326

Superconducting thin films for microwave resonators  

Microsoft Academic Search

YBCO high temperature superconducting thin films were off-axis deposited by RF magnetron sputtering onto yttria stabilised zirconia. The critical temperature Tc, the current density Jc, and the SEM structure were analysed. Also, the quality factor Q, was also investigated for microstrip resonators

R. Ramer; M. G. Banciu; C. Constantin; G. J. Russel; T. B. Vu

1997-01-01

327

Welding Wires To Thin Thermocouple Films  

NASA Technical Reports Server (NTRS)

Parallel-gap resistance welding yields joints surviving temperatures of about 1,000 degrees C. Much faster than thermocompression bonding. Also exceeds conductive-paste bonding and sputtering thin films through porous flame-sprayed insulation on prewelded lead wires. Introduces no foreign material into thermocouple circuit and does not require careful control of thickness of flame-sprayed material.

Holanda, Raymond; Kim, Walter S.; Danzey, Gerald A.; Pencil, Eric; Wadel, Mary

1993-01-01

328

Microscale heat conduction in dielectric thin films  

Microsoft Academic Search

Starting from fundamental principles, it is shown that heat conduction by phonons can be analyzed in radiative transfer. A general theory of heat conduction is developed, showing that the Fourier law is a limiting case for steady-state macroscale heat transport. Two cases of heat transport across and along a thin film are considered. For the transient case, the theory shows

A. Majumdar

1993-01-01

329

UV absorption control of thin film growth  

DOEpatents

A system for monitoring and controlling the rate of growth of thin films in an atmosphere of reactant gases measures the UV absorbance of the atmosphere and calculates the partial pressure of the gases. The flow of reactant gases is controlled in response to the partial pressure.

Biefeld, Robert M. (Albuquerque, NM); Hebner, Gregory A. (Albuquerque, NM); Killeen, Kevin P. (Albuquerque, NM); Zuhoski, Steven P. (Hopewell Junction, NY)

1991-01-01

330

Synthesis and characterization of multiferroic thin films  

Microsoft Academic Search

Multiferroic materials and multiferroic materials systems which simultaneously exhibit ferroelectricity and magnetism have attracted great attention because of their exotic physical properties and their potential applications which utilize coupling of magnetism and ferroelectricity. The goal of this thesis was to study multiferroic materials systems in thin film and multilayer forms in order to explore the possibility of fabricating room temperature

Sung Hwan Lim

2008-01-01

331

Thin film hydrous metal oxide catalysts  

DOEpatents

Thin film (<100 nm) hydrous metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

Dosch, Robert G. (Albuquerque, NM); Stephens, Howard P. (Albuquerque, NM)

1995-01-01

332

US polycrystalline thin film solar cells program  

SciTech Connect

The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R D on copper indium diselenide and cadmium telluride thin films. The objective of the Program is to support research to develop cells and modules that meet the US Department of Energy's long-term goals by achieving high efficiencies (15%-20%), low-cost ($50/m{sup 2}), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The US Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe{sub 2} and CdTe with subcontracts to start in Spring 1990. 23 refs., 5 figs.

Ullal, H.S.; Zweibel, K.; Mitchell, R.L. (Solar Energy Research Inst., Golden, CO (USA)) [Solar Energy Research Inst., Golden, CO (USA)

1989-11-01

333

Thin film ferroelectric materials for microbolometer arrays  

Microsoft Academic Search

This paper reviews the use of thin film ferroelectric materials for application in microbolometer infrared detector arrays. A key issue is the need for high temperature processing to achieve the required ferroelectric crystal phase. Results of thermal trials on silicon readout circuits are presented which indicate failure due to disruption of the AlCuSi metallisation. Higher temperatures can be used if

Michael A. Todd; Paul A. Manning; Paul P. Donohue; Alan G. Brown; Rex Watton

2000-01-01

334

Titanium nitride thin films for minimizing multipactoring  

Microsoft Academic Search

The invention discloses a method and apparatus for applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the

1979-01-01

335

Titanium nitride thin films for minimizing multipactoring  

Microsoft Academic Search

Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side

Kimo M

1979-01-01

336

Haemocompatibility of carbon based thin films  

Microsoft Academic Search

Haemocompatibility is one of the most important properties that determine the biocompatibility of the artificial implants. The haemocompatibility testing is to look for possible undesirable effects (e.g., haemolysis, thrombus formation, alterations in coagulation) in the blood, caused by a medical device or by chemicals leaching from a device. Carbon based thin films, such as amorphous carbon (a-C) and amorphous hydrogenated

S. Logothetidis

2007-01-01

337

Ternary Compound Thin Film Solar Cells.  

National Technical Information Service (NTIS)

The status of the CuInSe2/CdS heterojunction is discussed. An efficiency of 5.7% is reported for a device illuminated through the CdS layer. I-V and spectral response characteristics are presented. The first thin film CuInS2 homojunction photovoltaic devi...

L. L. Kazmerski

1976-01-01

338

Ternary Compound Thin Film Solar Cells.  

National Technical Information Service (NTIS)

The further characterization of the CuInX2 (X=S, Se, Te) is presented in this report. Specifically, photoconductivity effects in these chalcopyrite thin films are examined. Two areas of investigation are reported: (1) Photoconductivity Spectra, which give...

L. L. Kazmerski

1976-01-01

339

Trapping Effects in Organic Thin Film Transistors  

Microsoft Academic Search

We report the fabrication of pentacene thin film transistors with a mobility of 2.17 cm2\\/Vs which is challenging amorphous silicon. Next to device mobility, large hysteresis in the IV characteristics has been an obstacle for the design of large organic circuits in the past. It is a key success factor for optimization and widespread application of organic devices to understand

C. Erlen; F. Brunetti; P. Lugli; M. Fiebig; S. Schiefer; B. Nickel

2006-01-01

340

Analysis of hydrogen isotopes in thin films  

Microsoft Academic Search

Mass spectrometer modifications made for high resolution analysis of hydrogen isotopes outgassed from occluder thin films are described. The electronic modifications made to the source, magnet power supply, and scanning circuits provided increased precision in the mass range 2 to 6. Routine analyses were made at a resolution of 1300 with a Faraday cup detector. Extensive modification of the inlet

T. K. Mehrhoff; J. O. Humphries

1976-01-01

341

Thin-Film Microwave Integrated Circuits  

Microsoft Academic Search

There has been an increase in the use of thin-film technology for the preparation of microwave circuits since it permits the realization of very complex circuitry with precision, reliability, and economy. The requirements for the realization of such circuits have made it necessary to extend the state of the art of the hybrid technology in many areas. Two new substrate

VICTOR S. ARAMATI; J. SAMUEL BITLER; ARNOLD PFAHNL; C. C. SHIFLETT

1976-01-01

342

Rim instability of bursting thin smectic films  

NASA Astrophysics Data System (ADS)

The rupture of thin smectic bubbles is studied by means of high speed video imaging. Bubbles of centimeter diameter and film thicknesses in the nanometer range are pierced, and the instabilities of the moving rim around the opening hole are described. Scaling laws describe the relation between film thickness and features of the filamentation process of the rim. A flapping motion of the retracting smectic film is assumed as the origin of the observed filamentation instability. A comparison with similar phenomena in soap bubbles is made. The present experiments extend studies on soap films [H. Lhuissier and E. Villermaux, Phys. Rev. Lett. 103, 054501 (2009)] to much thinner, uniform films of thermotropic liquid crystals.

Trittel, Torsten; John, Thomas; Tsuji, Kinko; Stannarius, Ralf

2013-05-01

343

Electronic transport properties of topological insulator films and low dimensional superconductors  

NASA Astrophysics Data System (ADS)

In this review, we present a summary of some recent experiments on topological insulators (TIs) and superconducting nanowires and films. Electron-electron interaction (EEI), weak anti-localization (WAL) and anisotropic magneto-resistance (AMR) effect found in topological insulator films by transport measurements are reported. Then, transport properties of superconducting films, bridges and nanowires and proximity effect in non-superconducting nanowires are described. Finally, the interplay between topological insulators and superconductors (SCs) is also discussed.

Xing, Ying; Sun, Yi; Singh, Meenakshi; Zhao, Yan-Fei; Chan, Moses H. W.; Wang, Jian

2013-10-01

344

Crystalline silicon thin films for thin-film transistor applications via excimer laser irradiation  

Microsoft Academic Search

This dissertation documents the demonstration, development, and characterization of a new excimer laser crystallization process called sequential lateral solidification (SLS). The SLS process can provide thin-film materials with previously unavailable microstructures, such as location-controlled single-crystal islands and other low-defect-density engineered crystalline microstructures in thin silicon films on substrates that cannot withstand high-temperature processing. These materials are well-suited for making high-performance

Robert Stephen Sposili

2001-01-01

345

Thin film preparation of semiconducting iron pyrite  

NASA Astrophysics Data System (ADS)

Pyrite (Fe52) has been investigated as a promising new absorber material for thin film solar cell applications because of its high optical absorption coefficient of 1OL cm1, and its bandgap of 0.9 to 1.0 eV. Thin layers have been prepared by Metal Organic Chemical Vapor Deposition, MOCVD, Chemical Spray Pyrolysis, CSP, Chemical Vapor Transport, CVT, and Sulfurization of Iron Oxide films, 510. It is postulated that for the material FeS2, if x is not zero, a high point defect concentration results from replacing 2 dipoles by single S atoms. This causes the observed photovoltages and solar conversion efficiencies to be lower than expected. Using the Fe-O-S ternary phase diagram and the related activity plots, a thermodynamic understanding is formulated for the resulting composition of each of these types of films. It is found that by operating in the oxide portion of the phase diagram, the resulting oxidation state favors pyrite formation over FeS. By proper orientation of the grains relative to the film surface, and by control of pinholes and stoichiometry, an efficient thin film photovolatic solar cell material could be achieved.

Smestad, Greg P.; Ennaoui, Ahmed; Fiechter, Sebastian; Hofmann, Wolfgang; Tributsch, Helmut; Kautek, Wolfgang

1990-08-01

346

Antiferromagnetism in UO2 thin epitaxial films  

NASA Astrophysics Data System (ADS)

Thin films (250-4500 ) of epitaxial UO2 were produced by reactive sputtering on two different substrate materials: LaAlO3 and CaF2. Using the large enhancement present with resonant x-ray scattering using photons at the uranium M4 absorption edge, antiferromagnetic (AF) order was found in all films. The ordering temperature TN is the same as the bulk, but the films show second-order (continuous) transitions in contrast to the first-order bulk transition. For LaAlO3-based films, an additional strong diffuse magnetic disorder is observed, which is reminiscent of the second-length scale, associated with structural disorder and/or strain. By using a formulation accounting for the strong absorption and coherent nature of the photons, the energy widths at the U M4 resonances can be related to the thickness of the AF region. The LaAlO3-based films do not order magnetically over more than 600 , whereas the CaF2-based film orders throughout. Further, for thicker films (>1000 ) the fitting procedure shows that the AF order is located at the top of the LaAlO3-based film. This points to the formation in thicker films of a nonmagnetic layer of UO2 adjacent to the substrate, which may have tetragonal symmetry.

Bao, Z.; Springell, R.; Walker, H. C.; Leiste, H.; Kuebel, K.; Prang, R.; Nisbet, G.; Langridge, S.; Ward, R. C. C.; Gouder, T.; Caciuffo, R.; Lander, G. H.

2013-10-01

347

MISSE 5 Thin Films Space Exposure Experiment  

NASA Technical Reports Server (NTRS)

The Materials International Space Station Experiment (MISSE) is a set of space exposure experiments using the International Space Station (ISS) as the flight platform. MISSE 5 is a co-operative endeavor by NASA-LaRC, United Stated Naval Academy, Naval Center for Space Technology (NCST), NASA-GRC, NASA-MSFC, Boeing, AZ Technology, MURE, and Team Cooperative. The primary experiment is performance measurement and monitoring of high performance solar cells for U.S. Navy research and development. A secondary experiment is the telemetry of this data to ground stations. A third experiment is the measurement of low-Earth-orbit (LEO) low-Sun-exposure space effects on thin film materials. Thin films can provide extremely efficacious thermal control, designation, and propulsion functions in space to name a few applications. Solar ultraviolet radiation and atomic oxygen are major degradation mechanisms in LEO. This paper is an engineering report of the MISSE 5 thm films 13 months space exposure experiment.

Harvey, Gale A.; Kinard, William H.; Jones, James L.

2007-01-01

348

Molecular Recoiling in Polymer Thin Film Dewetting  

NASA Astrophysics Data System (ADS)

The molecular recoiling force stemming from nonequilibrium chain conformation was found to play a very important role in the dewetting stability of polymer thin films. Correct measurements and inclusion of this molecular force into thermodynamic consideration are crucial for analyzing dewetting phenomena and nanoscale polymer chain physics. This force was measured using a simple method based on contour relaxation at the incipient dewetting holes. The recoiling stress was found to increase dramatically with molecular weight and decreasing film thickness. The corresponding forces were calculated to be in the range from 9.0 to 28.2mN/m, too large to be neglected when compared to the dispersive forces (10mN/m) commonly operative in thin polymer films.

Yang, M. H.; Hou, S. Y.; Chang, Y. L.; Yang, A. C.-M.

2006-02-01

349

Directed Dewetting of Thin Polymer Films  

NASA Astrophysics Data System (ADS)

We present a simple route to generate arrays of microscale polygons by directed dewetting of polystyrene thin films on topographic pre-patterns.ootnotetextYoon et al., Soft Matter, 2008, 4, 1467-1472. Silicon wafers are patterned with arrays of ca. 10 ?m wide hexagonal holes using photolithography and wet etching. Patterned substrates are coated with thin films of polystyrene and heated above the glass transition temperature to promote dewetting. The dewetting process is monitored in-situ with optical microscopy, and final droplet structures are also imaged with atomic force microscopy. The mechanism of polygon formation is driven by Rayleigh instability; Formation rates and final polygon size are controlled by temperature/viscosity, film thickness, and the geometry of the topographic pre-pattern.

Moungthai, Suchanun; Pham, Trang; Rajaendran, Gus; Stein, Gila

2011-03-01

350

A magnetron sputtering system for the preparation of patterned thin films and in situ thin film electrical resistance measurements  

SciTech Connect

We describe a versatile three gun magnetron sputtering system with a custom made sample holder for in situ electrical resistance measurements, both during film growth and ambient changes on film electrical properties. The sample holder allows for the preparation of patterned thin film structures, using up to five different shadow masks without breaking vacuum. We show how the system is used to monitor the electrical resistance of thin metallic films during growth and to study the thermodynamics of hydrogen uptake in metallic thin films. Furthermore, we demonstrate the growth of thin film capacitors, where patterned films are created using shadow masks.

Arnalds, U. B.; Agustsson, J. S.; Ingason, A. S.; Eriksson, A. K.; Gylfason, K. B.; Gudmundsson, J. T.; Olafsson, S. [Matvice, Dunhaga 3, IS-107 Reykjavik (Iceland); Mentis Cura ehf., Grandagardi 7, IS-107 Reykjavik (Iceland); Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Microsystem Technology Laboratory, School of Electrical Engineering, KTH-Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland) and Department of Electrical and Computer Engineering, University of Iceland, Hjardarhaga 2-6, IS-107 Reykjavik (Iceland); Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland)

2007-10-15

351

Electrolyte and Electrode Passivation for Thin Film Batteries  

NASA Technical Reports Server (NTRS)

Passivation films for thin film batteries have been prepared and the conductivity and voltage stability window have been measured. Thin films of Li2CO3 have a large voltage stability window of 4.8V, which facilitates the use of this film as a passivation at both the lithium anode-electrolyte interface at high cathodic potentials.

West, W.; Whitacre, J.; Ratnakumar, B.; Brandon, E.; Blosiu, J.; Surampudi, S.

2000-01-01

352

WO 3 sputtered thin films for NO x monitoring  

Microsoft Academic Search

We present in this paper preliminary results concerning the preparation of tungsten trioxide thin films by reactive sputtering, the characterization either of their structural properties by means of XRD measurements or of the film morphology with the AFM microscope and the electrical response of the film towards toxic and pollutant gases. WO3 thin films showed a good sensitivity towards low

G. Sberveglieri; L. Depero; S. Groppelli; P. Nelli

1995-01-01

353

The calculation of thin film parameters from spectroscopic ellipsometry data  

Microsoft Academic Search

Spectroscopic ellipsometry (SE) has proven to be a very powerful diagnostic for thin film characterization, but the results of SE experiments must first be compared with calculations to determine thin film parameters such as film thickness and optical functions. This process requires four steps. (1) The quantities measured must be specified and the equivalent calculated parameters identified. (2) The film

G. E. Jellison; G. E. Jr

1996-01-01

354

Thin-film semiconductor rectifier has improved properties  

NASA Technical Reports Server (NTRS)

Cadmium selenide-zinc selenide film is used as a thin film semiconductor rectifier. The film is vapor-deposited in a controlled concentration gradient into a glass substrate to form the required junctions between vapor-deposited gold electrodes.

1966-01-01

355

Thin Film Rheology of Boundary Lubricating Surface Films. Part 3.  

National Technical Information Service (NTIS)

The principal objective of the program is to obtain a more fundamental understanding of the chemistry and physics of thin films of liquids in contact with solid substrates and the application of this understanding to the development of more systematic met...

E. Drauglis C. M. Allen J. W. Droege D. Ensminger R. J. Jakobsen

1972-01-01

356

Thin microstructured polymer films by surface-directed film formation  

Microsoft Academic Search

Evaporated gold films are hydrophilized within well defined areas of several micrometer size by microcontact printing of 11-mercapto-undecanoic acid. The localized hydrophilizing of the surface controls the formation of water microdroplets within these areas due to preferred condensation from a water saturated atmosphere. The preparation of regular well defined condensation patterns of water microdroplets is necessary to obtain structured thin

H.-G. Braun; E. Meyer

1999-01-01

357

Electrodeposition of CdTe thin films  

SciTech Connect

Cadmium telluride thin films were fabricated on Ti and Nesatron substrates by electrodeposition and characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analyses (EDAX), optical transmission measurements, and photoelectrochemical (PEC) studies. The deposition-bath preparation procedure was slightly modified from the literature method to permit initial speciation of TeO/sub 2/ and thereby increase the loading level of Te in the film. New data are presented on the electrochemistry of the deposition process and on the cyclic voltammetric behavior of TeO/sub 2/ containing electrolytes in the pH range from about 0.7 to 11.0. The films after suitable annealing in an Ar atmosphere show x-ray diffraction behavior consistent with a hexagonal structure. Data from EDAX show that the Cd/Te ratio in the film is sensitive to the annealing process. Concomitantly, the conductivity also changes from p-type to n-type, as shown by PEC measurements on the films containing a protective ..cap alpha..-PbO/sub 2/ coating in contact with alkaline polysulfide electrolytes. Finally, some preliminary data are presented on PEC cells based on these CdTe thin films in a nonaqueous electrolyte system comprising the ferrocene/ferricenium ion redox couple.

Bhattachurya, R.N.; Rajeshwar, K.

1984-09-01

358

Thin film memory device having a variable resistance  

US Patent & Trademark Office Database

A thin film storage device includes a first electrode (3), a first variable resistance thin film (2), and a second electrode (1). The first electrode (3) is formed over a surface of a substrate (4). The first variable resistance thin film (2) is formed over a surface of the first electrode (3). The second electrode (1) is formed over a surface of the first variable resistance thin film (2). The first variable resistance thin film (2) comprises a material whose resistance in a bulk state changes in accordance with at least one of a lattice strain and a change of charge-order.

2012-09-11

359

Metallophthalocyanine thin films: Structure and physical properties  

NASA Astrophysics Data System (ADS)

Organic semiconductors represent a class of carbon-based compounds with a tremendous potential to exhibit novel physical properties, and to be used in new and important applications. They display different properties compared to their inorganic counterparts, and present many advantages such as unlimited potential to be synthesized in new molecular structures, and capability of being processed inexpensively. Metallophthalocyanines (MPc) belong to the small-molecule group of organic semiconductors, and represent a model system for the whole class of flat, organic molecules. This dissertation presents a study of the structure and the electrical and magnetic properties of thin phthalocyanine films and phthalocyanine-based devices. Chapter one gives an introduction to the general properties of organic semiconductors and the wide range of their physical properties. In particular, the metallophtalocyanines are introduced as being a model system for the small-molecule group of organic semiconductors. Metallophthalocyanines are very well suited to be grown in thin films using organic molecular beam deposition (OMBD) techniques. Chapter two discusses the fabrication of thin phthalocyanine films and devices using OMBD, and the study of their structural properties using a wide range of experimental methods. The molecular shape anisotropy, combined with the interplay between intermolecular and the molecule-substrate interactions, determine different thin film structures that can be controlled by the fabrication conditions. The structure of phthalocyanine thin films determines their electrical transport properties. Chapter three investigates the electrical transport properties of hybrid metal-organic sandwich devices. These properties are controlled not only by the organic film, but also by the metal-organic interfaces. It was found that the low-voltage regime is linear, i.e. Ohmic, for a wide range of temperatures and organic layer thicknesses. The conductance increases exponentially with the temperature and decreases exponentially with the thickness. This behavior was explained with a model that incorporates tunneling between localized states with thermally-induced overlap. Chapter 4 studies the magnetic properties of MPcs. They are controlled by the central metal ion, and the type of molecular stacking in thin films, and were studied using DC magnetometry and magneto-optical techniques. Experimental data suggest the existence of two different magnetic regimes as a function of temperature.

Colesniuc, Corneliu Nicolai

360

Investigation of TiOx barriers for their use in hybrid Josephson and tunneling junctions based on pnictide thin films  

NASA Astrophysics Data System (ADS)

We tested oxidized titanium layers as barriers for hybrid Josephson junctions with high IcRn-products and for the preparation of junctions for tunneling spectroscopy. For that we firstly prepared junctions with conventional superconductor electrodes, such as lead and niobium, respectively. By tuning the barrier thickness, we were able to change the junction's behavior from a Josephson junction to tunnel-like behavior applicable for quasi-particle spectroscopy. Subsequently, we transferred the technology to junctions using Co-doped BaFe2As2 thin films prepared by pulsed laser deposition as base electrode and evaporated Pb as counter electrode. For barriers with a thickness of 1.5 nm, we observe clear Josephson effects with IcRn?90 ?V at 4.2 K. These junctions behave SNS'-like (SNS: superconductor-normal conductor-superconductor) and are dominated by Andreev reflection transport mechanism. For junctions with barrier thickness of 2.0 nm and higher, no Josephson but SIS'- (SIS: superconductor-insulator-superconductor) or SINS'-like (SINS: superconductor-normal conductor-insulator-superconductor) behavior with a tunnel-like conductance spectrum was observed.

Dring, S.; Monecke, M.; Schmidt, S.; Schmidl, F.; Tympel, V.; Engelmann, J.; Kurth, F.; Iida, K.; Haindl, S.; Mnch, I.; Holzapfel, B.; Seidel, P.

2014-02-01

361

Transport behavior across the field-driven superconductor-insulator transition in amorphous indium oxide films  

NASA Astrophysics Data System (ADS)

Superconductor-insulator transition (SIT) in two-dimensional (2D) thin films is a beautiful realization of a zero temperature quantum phase transition (QPT) and has been explored both theoretically and experimentally over the last two decades. In addition to the several intrinsic ways (such as thickness) of tuning the transition, external magnetic field has been used to tune from one ground state to another in various condensed matter systems. Amorphous indium oxide thin films, with their unique capability of tuning the disorder level in the system easily, have been proven to be an excellent model system to study the transport mechanisms near and across the SIT in 2D. In this thesis, magnetic field-driven SIT in 2D films of amorphous InO x is studied. The goal of this work is to understand the microscopic transport mechanisms responsible for driving the SIT when the magnetic field direction is continually varied from being perpendicular to the sample plane to parallel. Applying a perpendicular magnetic field resulting in a clear field-driven SIT and a magneto-resistance peak on the insulating side in InO x films have been previously understood in a bosonic picture put forward by M. P. A. Fisher and coworkers. However, this boson-vortex duality picture is expected to give rise to markedly different transport characteristics when the magnetic field is applied parallel to the sample plane. Features found in the parallel-field transport data however can also be explained by the bosonic picture, thereby questioning the applicability of the hitherto successful models to the physics of SIT. An isotropic magnetic field value, where the sample has the exact same resistance irrespective of the angle between the sample plane and magnetic field direction, is found. This isotropic point lies at field values above the critical field (Bc) of the SIT (in both perpendicular and parallel configurations) and above the magnetoresistance peak. The isotropic point is very weakly dependent on disorder levels and is temperature-independent. These observations suggest a possible fermionic role in the conduction near the quantum critical point of the SIT and would require newer models to be developed to completely understand the physics. Current-voltage characteristics measured in superconducting samples (below Bc) show that the true superconducting behavior (with a critical current to conduction) appears only in the B = 0 limit. Especially, application of a small magnetic field ( 0.2 T) drives the system into a flux flow regime and hence dissipative. The role of this dissipative channel in the superconducting phase in driving the SIT is not well understood. Competing roles of dissipation and bosonic mechanisms need to be treated simultaneously to decipher the underlying physics. When magnetic field is applied to a mesoscopic scale superconducting film, the film breaks into puddles of superconductors and insulators, thereby suggesting percolation-type transport behavior near the quantum critical point. Interestingly, the nonuniform nature of conduction occurs only in magnetic fields below and above Bc at very low temperature below 400 mK and the sample is completely homogeneous at B c. A complete understanding of the scale of inhomogeneous regions and their role in driving the QPT are still unclear. And the results presented suggest that more experimental and theoretical efforts are needed for understanding the physics near the QPT clearly.

Kim, Min-Soo

362

Numerical simulations of thin film thermal flow  

NASA Astrophysics Data System (ADS)

The thin film thermal flow process in long trenches is analyzed using a simulator which solves the equations which govern viscous, incompressible fluid flow. The total thermal baking process is divided into small time steps. At each time step, we solve the governing equations using the penalty function formulation and the Galerkin finite element method to obtain local velocity vectors. The free surface of the flowing film is updated according to these local velocity vectors. As an example application, we simulate the flow of boron and phosphorus doped silicon dioxide glass films in 2 micrometer high by 2 micrometer wide, infinitely long trenches, for which two-dimensional profile evolution is appropriate. The simulated film profiles show that the local leveling rate of a film is a sensitive function of surface curvature. The simulation program predicts that lower viscosity and thicker films have superior planarization properties compared with higher viscosity and thinner films. These trends are in agreement with empirical observations and previous modeling and simulation work on glass film planarization processes.

Liao, Hung; Cale, Timothy S.

1994-12-01

363

Fabrication and characterization of amorphous lithium electrolyte thin films and rechargeable thin-film batteries  

Microsoft Academic Search

Amorphous oxide and oxynitride lithium electrolyte thin films were synthesized by r.f. magnetron sputtering of lithium silicates and lithium phosphates in Ar, Ar + O2, Ar + N2, or N2. The composition, structure, and electrical properties of the films were characterized using ion and electron beam, X ray, optical, photoelectron, and a.c. impedance techniques. For the lithium phosphosilicate films, lithium

J. B. Bates; N. J. Dudney; G. R. Gruzalski; R. A. Zuhr; A. Choudhury; C. F. Luck; J. D. Robertson

1993-01-01

364

Ferroelectric Thin Films for Electronic Applications  

NASA Astrophysics Data System (ADS)

This study yokes together the feasibility of a family of PbO-based perovskite-structured ferroelectric thin films as functional elements in nonvolatile random access memories (NVRAMs), in high capacity dynamic RAMs, and in a new class of flexure wave piezoelectric ultrasonic micromotors. The dielectric and ferroelectric properties of lead zirconate titanate (PZT) thin films were dependent on thickness; at saturation, the films were characterized by a relative permittivity of 1300, remanent polarization of 36 muC/cm^2 and breakdown strength of over 1 MV/cm. The temperature dependence of permittivity revealed an anomalous behavior with the film annealing temperature. Based on the ferroelectric properties in the bulk, thin films in the lead zirconate -lead zinc niobate (PZ-PZN) solid solution system at 8-12% PZN, examined as alternate compositions for ferroelectric memories, feature switched charges of 4-14 mu C/cm^2, with coercive and saturation voltages less than the semiconductor operating voltage of 5 V. Rapid thermally annealed lead magnesium niobate titanate films were privy to weak signal dielectric permittivity of 2900, remanent polarization of 11 muC/cm^2, and a storage density of 210 fC/mum^2 at 5 V; the films merit consideration for potential applications in ultra large scale integrated circuits as also ferroelectric nonvolatile RAMs. The high breakdown strength and relative permittivity of the PZT films entail maximum stored energy density 10^3 times larger than a silicon electrostatic motor. The longitudinal piezoelectric strain coefficient d_{33 } was measured to be 220 pC/N at a dc bias of 75 kV/cm. The transverse piezoelectric strain coefficient d_{31} bore a nonlinear relationship with the electric field; at 200 kV/cm, d _{31} was -88 pC/N. The development of the piezoelectric ultrasonic micromotors from the PZT thin films, and the architecture of the stator structures are described. Nonoptimized prototype micromotors show rotational velocities of 100-300 rpm at drives of 3-5 V.

Udayakumar, K. R.

365

Thin film diamond microstructure applications  

NASA Technical Reports Server (NTRS)

Selective deposition and abrasion, as well as etching in atomic oxygen or reduced-pressure air, have been used to prepare patterned polycrystalline diamond films which, on further processing by anisotropic Si etching, yield the microstructures of such devices as flow sensors and accelerometers. Both types of sensor have been experimentally tested in the respective functions of hot-wire anemometer and both single- and double-hinged accelerometer.

Roppel, T.; Ellis, C.; Ramesham, R.; Jaworske, D.; Baginski, M. E.; Lee, S. Y.

1991-01-01

366

Polycrystalline thin film materials and devices  

SciTech Connect

Results of Phase II of a research program on polycrystalline thin film heterojunction solar cells are presented. Relations between processing, materials properties and device performance were studied. The analysis of these solar cells explains how minority carrier recombination at the interface and at grain boundaries can be reduced by doping of windows and absorber layers, such as in high efficiency CdTe and CuInSe{sub 2} based solar cells. The additional geometric dimension introduced by the polycrystallinity must be taken into consideration. The solar cells are limited by the diode current, caused by recombination in the space charge region. J-V characteristics of CuInSe{sub 2}/(CdZn)S cells were analyzed. Current-voltage and spectral response measurements were also made on high efficiency CdTe/CdS thin film solar cells prepared by vacuum evaporation. Cu-In bilayers were reacted with Se and H{sub 2}Se gas to form CuInSe{sub 2} films; the reaction pathways and the precursor were studied. Several approaches to fabrication of these thin film solar cells in a superstrate configuration were explored. A self-consistent picture of the effects of processing on the evolution of CdTe cells was developed.

Baron, B.N.; Birkmire, R.W.; Phillips, J.E.; Shafarman, W.N.; Hegedus, S.S.; McCandless, B.E. (Delaware Univ., Newark, DE (United States). Inst. of Energy Conversion)

1992-10-01

367

Borides in thin film technology  

SciTech Connect

The borides of transition and rare-earth metals are considered for application as wear- and corrosion-resistant, decorative or thermionic coatings. After a review of physical vapor deposition (PVD) techniques used for the deposition of these coatings, a survey of investigations to apply these coatings is given. As a result of the strong directionality of covalent boron-boron bonds, boride coatings show an increasing tendency to amorphous film growth with increasing B/Me atomic ratio and, for rare-earth hexaborides, with decreasing metallic radius of the rare-earth metal. Mechanical and optical properties are strongly influenced by the crystallographic structure of the boride phase. Because of their high hardness combined with good adhesion, crystalline films based on the diborides of transition metals seem to be promising candidates for wear resistant coatings on cutting tools. Alloying of these films with nitrogen by reactive PVD processes results in the formation of extremely fine-grained multiphase hard coatings with excellent tribological and corrosion behavior, thus offering new applications in the coating of engineering components. Because of their distinct colorations, some of the hexaborides of rare-earth elements may be used as decorative coatings on consumer products like wristwatch casings or eyeglass frames. Another promising field is the development of thermionic coatings based on rare-earth hexaborides, which may offer the possibility of the production of inexpensive and simple high emission filaments.

Mitterer, C. [Institut fuer Metallkunde und Werkstoffpruefung, Leoben (Austria)] [Institut fuer Metallkunde und Werkstoffpruefung, Leoben (Austria)

1997-10-01

368

Equilibrium microstructure of epitaxial thin films  

SciTech Connect

A theoretical study is presented of the equilibrium domain microstructure expected for a thin film grown epitaxially onto a single-crystal substrate as a function of temperature, film thickness, and lattice misfit for the case when the film can undergo a structural phase transition. The theory treats the epitaxial interface at the level of the Frenkel-Kontorova model and takes into account domain-wall energies and bulk-elasticity effects in both the film and the substrate. Existing predictions for this problem by Roitburd are reproduced when the epitaxial interface is commensurate. Results are obtained for the general case when the interface is incommensurate. The corresponding domain structure generically involves multiple phases.

Little, S.; Zangwill, A. (School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States))

1994-06-15

369

Polarization properties of thin films of diamond.  

PubMed

Thin films transparent to optical radiation offer polarization properties that are enhanced when the thickness of the film is an odd multiple of the quarter-wavelength. The transmission and reflection properties of a 1.16-?m-thick film of diamond realized by plasma-assisted chemical vapor deposition have been studied at 10.6 ?m. A compact polarizer built with four films at a Brewster angle revealed an extinction ratio of better than 1:1000 of the S polarization. The interest in optics in which parasitic-reflected or transmitted beams do not exist is pointed out. The high damage threshold of diamonds opens the possibility of controlling the polarization characteristics of high-power lasers used, for example, for soldering and cutting applications. PMID:21151249

Chardonnet, C; Bernard, V; Daussy, C; Gicquel, A; Anger, E

1996-12-01

370

O thin films prepared by electrodeposition  

NASA Astrophysics Data System (ADS)

Cuprous oxide (Cu2O) thin films were prepared by using electrodeposition technique at different applied potentials (-0.1, -0.3, -0.5, -0.7, and -0.9 V) and were annealed in vacuum at a temperature of 100C for 1 h. Microstructure and optical properties of these films have been investigated by X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), UV-visible (vis) spectrophotometer, and fluorescence spectrophotometer. The morphology of these films varies obviously at different applied potentials. Analyses from these characterizations have confirmed that these films are composed of regular, well-faceted, polyhedral crystallites. UV-vis absorption spectra measurements have shown apparent shift in optical band gap from 1.69 to 2.03 eV as the applied potential becomes more cathodic. The emission of FL spectra at 603 nm may be assigned as the near band-edge emission.

Jiang, Xishun; Zhang, Miao; Shi, Shiwei; He, Gang; Song, Xueping; Sun, Zhaoqi

2014-05-01

371

Raman spectra of magnesium chloride thin films  

NASA Astrophysics Data System (ADS)

We have observed lattice vibrations of MgCl 2 thin films for the first time by surface enhanced Raman scattering induced by a silver underlayer. Two Raman active bands of the MgCl 2 crystal, Eg and A1g, were observed at 160 and 240 cm -1. The band width of A1g mode was about 20 cm -1. The Raman spectra indicate that the lattice structure of the evaporated MgCl 2 film is well ordered like that of a polycrystal. We have also measured Raman intensity of A1g mode, varying the film thickness from 0.6 to 7 nm. This film thickness dependence indicates that the Raman enhancement occurs within a very short distance from the substrate.

Sano, H.; Miyaoka, H.; Kuze, T.; Mori, H.; Mizutani, G.; Otsuka, N.; Terano, M.

2002-04-01

372

A Multilayered Thin Film Insulator for Harsh Environments  

NASA Technical Reports Server (NTRS)

The status of work to develop a reliable high temperature dielectric thin film for use with thin film sensors is presented. The use of thin films to electrically insulate thin film sensors on engine components minimizes the intrusiveness of the sensor and allows a more accurate measurement of the environment. A variety of insulating films were investigated for preventing electrical shorting caused by insulator failure between the sensor and the component. By alternating layers of sputtered high temperature ceramics, a sequence of insulating layers was devised that prevents pinholes from forming completely through the insulator and maintains high electrical resistivity at high temperatures. The major technical challenge remaining is to optimize the fabrication of the insulator with respect to composition to achieve a reliable high temperature insulating film. Data from the testing of various potentially insulating thin film systems is presented and their application to thin film sensors is also discussed.

Wrbanek, John D.; Fralick, Gustave C.; Blaha, Charles A.; Busfield, A. Rachel; Thomas, Valarie D.

2002-01-01

373

Extending the 3? method: Thermal conductivity characterization of thin films  

NASA Astrophysics Data System (ADS)

A lock-in technique for measurement of thermal conductivity and volumetric heat capacity of thin films is presented. The technique is based on the 3? approach using electrical generation and detection of oscillatory heat along a thin metal strip. Thin films are deposited onto the backside of commercial silicon nitride membranes, forming a bilayer geometry with distinct thermal parameters. Stepwise comparison to an adapted heat diffusion model delivers these parameters for both layers. Highest sensitivity is found for metallic thin films.

Bodenschatz, Nico; Liemert, Andr; Schnurr, Sebastian; Wiedwald, Ulf; Ziemann, Paul

2013-08-01

374

Characteristics of thin film inductors using magnetic multilayered films with ceramic intermediate layers  

Microsoft Academic Search

Circular spiral thin film inductors were fabricated using as-deposited magnetic multilayered films with ceramic intermediate layers, and a thin film inductor with a single magnetic layer was also fabricated for comparison. The magnetic multilayered films have good soft magnetic properties and high resistivity thus can decrease the eddy current loss. Employing the magnetic multilayered films, we got a higher quality

Xiao-Li Tang; H. W. Zhang; H. Su; Y. Shi; X. D. Jiang

2005-01-01

375

Elastic Properties of Molecular Glass Thin Films  

NASA Astrophysics Data System (ADS)

This dissertation provides a fundamental understanding of the impact of bulk polymer properties on the nanometer length scale modulus. The elastic modulus of amorphous organic thin films is examined using a surface wrinkling technique. Potential correlations between thin film behavior and intrinsic properties such as flexibility and chain length are explored. Thermal properties, glass transition temperature (Tg) and the coefficient of thermal expansion, are examined along with the moduli of these thin films. It is found that the nanometer length scale behavior of flexible polymers correlates to its bulk Tg and not the polymers intrinsic size. It is also found that decreases in the modulus of ultrathin flexible films is not correlated with the observed Tg decrease in films of the same thickness. Techniques to circumvent reductions from bulk modulus were also demonstrated. However, as chain flexibility is reduced the modulus becomes thickness independent down to 10 nm. Similarly for this series minor reductions in T g were obtained. To further understand the impact of the intrinsic size and processing conditions; this wrinkling instability was also utilized to determine the modulus of small organic electronic materials at various deposition conditions. Lastly, this wrinkling instability is exploited for development of poly furfuryl alcohol wrinkles. A two-step wrinkling process is developed via an acid catalyzed polymerization of a drop cast solution of furfuryl alcohol and photo acid generator. The ability to control the surface topology and tune the wrinkle wavelength with processing parameters such as substrate temperature and photo acid generator concentration is also demonstrated. Well-ordered linear, circular, and curvilinear patterns are also obtained by selective ultraviolet exposure and polymerization of the furfuryl alcohol film. As a carbon precursor a thorough understanding of this wrinkling instability can have applications in a wide variety of technologies.

Torres, Jessica

376

Neutron Number Enhancement in Uranium Thin Film Waveguides  

NASA Astrophysics Data System (ADS)

The feasibility of the miniaturization of nuclear energy production is discussed. It is shown how the characteristics of 4 % enriched uranium thin film waveguides can be optimized in order to allow neutron concentration at high densities. The guiding uranium thin film is sandwiched between two ferromagnetic media. Since the neutron refractive index in thin magnetic films is spin dependent, this permits control of the neutron number in the uranium film by means of external magnetic fields.

Pogossian, S. P.

2010-04-01

377

Enhanced neutron concentration in uranium thin film waveguides  

NASA Astrophysics Data System (ADS)

The theoretical feasibility of the miniaturization of nuclear energy production is discussed. It is shown how the characteristics of 4% enriched uranium thin film waveguides can be optimized in order to allow neutron concentration at high densities. The guiding uranium thin film is sandwiched between two ferromagnetic media. Since the neutron refractive index in thin magnetic films is spin dependent, this permits control of the neutron number in the uranium film by means of external magnetic fields.

Pogossian, S. P.

2007-11-01

378

Gamma Radiation Dosimetry Using Tellurium Dioxide Thin Film Structures  

Microsoft Academic Search

Thin films of Tellurium dioxide (TeO2) were investigated for ?-radiation dosimetry purposes. Samples were fabricated using thin film vapour deposition technique. Thin films of TeO2 were exposed to a 60Co ?-radiation source at a dose rate of 6 Gy\\/min at room temperature. Absorption spectra for TeO2 films were recorded and the values of the optical band gap and energies of

Khalil Arshak; Olga Korostynska

2002-01-01

379

Photovoltaic Properties of Thin Polymer (PVK-TNF) Films  

NASA Astrophysics Data System (ADS)

The photovoltaic properties of thin films of the polyvinylcarbazole-trinitrofluorenone complex are investigated. Thin films of thickness between 10 and 500 nm were formed by the solution-casting method. The photovoltaic energy conversion efficiency was measured in Au-(polymer thin film)-Al cells as a function of the film thickness, and it became a maximum (about 0.01%) at a thickness of about 100 nm.

Yamashita, Ken; Suzuki, Tatsuya; Hino, Taro

1982-10-01

380

Nanoparticulate Alnico Thin Films with High Coercivity  

NASA Astrophysics Data System (ADS)

Alnico V (Fe--8% Al--14% Ni--24% Co--3% Cu) nanoparticulate thin films have been produced by dc magnetron sputtering. The films were sputtered on Si substrates for magnetic measurements and carbon-coated copper grids for TEM measurements. The as-deposited films have a fine grained microstructure with the bcc crystal structure. The as-made films were subjected to a full heat treatment which consists of heating the sample to 900 ^oC, then cooling it to 600 ^oC and finally annealing it at 600 ^oC for several hours. After the heat treatment, the thin films broke up into large nanoparticles (20-60 nm) surrounded by small nanoparticles (2 nm). Electron diffraction data showed that the annealed samples had an fcc structure. The maximum room temperature coercivity was found to be 2 kOe after 6h of annealing at 600 ^oC. The high coercivity could be due to strain that was induced during precipitation. The evolution of crystal structure and microstructure with annealing will be monitored and related to the observed magnetic properties.

Akdogan, Ozan; Hadjipanayis, George C.

2009-03-01

381

Thermal conductivities of thin, sputtered optical films  

SciTech Connect

The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO{sub 2}/Si{sub 3}N{sub 4}){sup n} and Al(Al{sub 2}O{sub 3}/AIN){sup n}. Sputtered films of more conventional materials like SiO{sub 2}, Al{sub 2}O{sub 3}, Ta{sub 2}O{sub 5}, Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented.

Henager, C.H. Jr.; Pawlewicz, W.T.

1991-05-01

382

Thin Film...Large Payoff  

NASA Technical Reports Server (NTRS)

SRS Technologies is currently the only company licensed by Langley Research Center to produce colorless polyimides. They currently produce two polyimides, the LaRC-CP1 and LaRC-CP2 developed by Langley Research Center. These polyimides offer many advantages over other commercially available materials including excellent thermal stability, radiation resistance, solubility, and transparency. The SRS polyimides can be used in laminates, films, molded parts, and stock shapes. The polyimide technology has also helped the company further their development of solar arrays.

1998-01-01

383

Cooperative Emission in ?-Conjugated Polymer Thin Films  

NASA Astrophysics Data System (ADS)

Picosecond dynamics of exciton emission and absorption have been studied in neat thin films of a variety of poly (phenylene vinylene) derivatives. We found that the stimulated emission band of 120 nm width and ~1 ns duration, which is observed at low exciton density n, collapses at n>1017 cm-3 into a much narrower band of 7 nm width and lifetime ?<<10 ps. Based on its excitation intensity dependence, polarization, lifetime, illuminated area, and film thickness dependencies, we assign this narrow band to superfluorescence rather than to amplified spontaneous emission.

Frolov, S. V.; Gellermann, W.; Ozaki, M.; Yoshino, K.; Vardeny, Z. V.

1997-01-01

384

Electrochromism in copper oxide thin films  

SciTech Connect

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a large dynamic range, from 85% and 10% photopic transmittance, with a coloration efficiency of about 32 cm2/C. Gradual deterioration of the switching range occurred over 20 to 100 cycles. This is tentatively ascribed to coarsening of the film and contact degradation caused by the 65% volume change on conversion of Cu to Cu2O. Switching between the two copper oxides (which have similar volumes) was more stable and more efficient (CE = 60 cm2/C), but covered a smaller transmittance range (60% to 44% T). Due to their large electrochemical storage capacity and tolerance for alkaline electrolytes, these cathodically coloring films may be useful as counter electrodes for anodically coloring electrode films such as nickel oxide or metal hydrides.

Richardson, T.J.; Slack, J.L.; Rubin, M.D.

2000-08-15

385

Magnetic Thin Films of Inorganic Nanosheets  

NASA Astrophysics Data System (ADS)

Molecule-based magnets have been fascinating materials because of the potential applications in information storage, electronic and spintronic devices. However, such applications would require arraying the active materials on a substrate or interfacing with other components. Here, we focus on fabricating multi-functional magnetic films using inorganic nanosheets as a building block. The thin films could be prepared by the modified Langmuir-Blodgett, LB, technique or the layer-by-layer, LbL, method, which are representative wet-processings for film preparation. As the magnetic LB film, we chose semiconductive titania nanosheets and magnetic Prussian Blue. Upon band gap excitation of titania nanosheets, electron injection into Prussian Blue was achieved with scavenging interlayer water molecules, leading to photoreduction to Prussian White. As the magnetic LbL film, we chose magnetic layered double hydroxide, LDH, nanosheets and non-magnetic smectite nanosheets. In powdered LDH, a coercivity increased with expanding the interlayer spacing. On the other hand, despite the larger interlayer spacing for the LbL film, a coercivity was less than that of the comparative powdered LDH. It is indicated LDH nanosheets are integrated in an anisotropic manner in the LbL films.

Yamamoto, Takashi; Namba, Hiroaki; Einaga, Yasuaki

2012-02-01

386

Synthesis of ?-Mo(2)C thin films.  

PubMed

Thin films of stoichiometric ?-Mo(2)C were fabricated using a two-step synthesis process. Dense molybdenum oxide films were first deposited by plasma-enhanced chemical vapor deposition using mixtures of MoF(6), H(2), and O(2). The dependence of operating parameters with respect to deposition rate and quality is reviewed. Oxide films 100-500 nm in thickness were then converted into molybdenum carbide using temperature-programmed reaction using mixtures of H(2) and CH(4). X-ray diffraction confirmed that molybdenum oxide is completely transformed into the ?-Mo(2)C phase when heated to 700 C in mixtures of 20% CH(4) in H(2). The films remained well-adhered to the underlying silicon substrate after carburization. X-ray photoelectron spectroscopy detected no impurities in the films, and Mo was found to exist in a single oxidation state. Microscopy revealed that the as-deposited oxide films were featureless, whereas the carbide films display a complex nanostructure. PMID:21250643

Wolden, Colin A; Pickerell, Anna; Gawai, Trupti; Parks, Sterling; Hensley, Jesse; Way, J Douglas

2011-02-01

387

High T(sub c) superconductors from metallorganic precursors  

NASA Astrophysics Data System (ADS)

High T(sub c) cuprate superconductors have been made by pyrolysis of metallorganic precursors (polyacrylic acid and acetates) incorporating the appropriate molar ratios of metal ions to form the desired copper oxide compounds. Two processes have been described as representative examples of novel strategies to produce high T(sub c) superconductors in bulk and thin film form: pyrolysis of metallorganic powders for bulk processing and spray pyrolysis for thin film fabrication.

Wang, Y. L.; Chou, W. T.; Skotheim, T.; Budhani, R.; Suenaga, M.; Okamoto, Y.

388

Effect of annealing on the superconducting properties of a-NbxSi1-x thin films  

NASA Astrophysics Data System (ADS)

a-NbxSi1-x thin films with thicknesses down to 25 have been structurally characterized by transmission electron microscopy measurements. As-deposited or annealed films are shown to be continuous and homogeneous in composition and thickness, up to an annealing temperature of 500 ?C. We have carried out low-temperature transport measurements on these films close to the superconductor-to-insulator transition (SIT) and shown a qualitative difference between the effect of annealing or composition and a reduction of the film thickness on the superconducting properties of a-NbSi. These results question the pertinence of the sheet resistance R? as the relevant parameter to describe the SIT.

Crauste, O.; Gentils, A.; Coudo, F.; Dolgorouky, Y.; Berg, L.; Collin, S.; Marrache-Kikuchi, C. A.; Dumoulin, L.

2013-04-01

389

EBSD analysis of electroplated magnetite thin films  

NASA Astrophysics Data System (ADS)

By means of electron backscatter diffraction (EBSD), we analyse the crystallographic orientation of electroplated magnetite thin films on Si/copper substrates. Varying the voltage during the electroplating procedure, the resulting surface properties are differing considerably. While a high voltage produces larger but individual grains on the surface, the surfaces become smoother on decreasing voltage. Good quality Kikuchi patterns could be obtained from all samples; even on individual grains, where the surface and the edges could be measured. The spatial resolution of the EBSD measurement could be increased to about 10 nm; thus enabling a detailed analysis of single magnetite grains. The thin film samples are polycrystalline and do not exhibit a preferred orientation. EBSD reveals that the grain size changes depending on the processing conditions, while the detected misorientation angles stay similar.

Koblischka-Veneva, A.; Koblischka, M. R.; Teng, C. L.; Ryan, M. P.; Hartmann, U.; Mcklich, F.

2010-05-01

390

Thin film strain gage development program  

NASA Technical Reports Server (NTRS)

Sputtered thin-film dynamic strain gages of 2 millimeter (0.08 in) gage length and 10 micrometer (0.0004 in) thickness were fabricated on turbojet engine blades and tested in a simulated compressor environment. Four designs were developed, two for service to 600 K (600 F) and two for service to 900 K (1200 F). The program included a detailed study of guidelines for formulating strain-gage alloys to achieve superior dynamic and static gage performance. The tests included gage factor, fatigue, temperature cycling, spin to 100,000 G, and erosion. Since the installations are 30 times thinner than conventional wire strain gage installations, and any alteration of the aerodynamic, thermal, or structural performance of the blade is correspondingly reduced, dynamic strain measurement accuracy higher than that attained with conventional gages is expected. The low profile and good adherence of the thin film elements is expected to result in improved durability over conventional gage elements in engine tests.

Grant, H. P.; Przybyszewski, J. S.; Anderson, W. L.; Claing, R. G.

1983-01-01

391

Thin film photovoltaic panel and method  

DOEpatents

A thin film photovoltaic panel includes a backcap for protecting the active components of the photovoltaic cells from adverse environmental elements. A spacing between the backcap and a top electrode layer is preferably filled with a desiccant to further reduce water vapor contamination of the environment surrounding the photovoltaic cells. The contamination of the spacing between the backcap and the cells may be further reduced by passing a selected gas through the spacing subsequent to sealing the backcap to the base of the photovoltaic panels, and once purged this spacing may be filled with an inert gas. The techniques of the present invention are preferably applied to thin film photovoltaic panels each formed from a plurality of photovoltaic cells arranged on a vitreous substrate. The stability of photovoltaic conversion efficiency remains relatively high during the life of the photovoltaic panel, and the cost of manufacturing highly efficient panels with such improved stability is significantly reduced.

Ackerman, Bruce (El Paso, TX); Albright, Scot P. (El Paso, TX); Jordan, John F. (El Paso, TX)

1991-06-11

392

Substrate heater for thin film deposition  

DOEpatents

A substrate heater for thin film deposition of metallic oxides upon a target substrate configured as a disk including means for supporting in a predetermined location a target substrate configured as a disk, means for rotating the target substrate within the support means, means for heating the target substrate within the support means, the heating means about the support means and including a pair of heating elements with one heater element situated on each side of the predetermined location for the target substrate, with one heater element defining an opening through which desired coating material can enter for thin film deposition and with the heating means including an opening slot through which the target substrate can be entered into the support means, and, optionally a means for thermal shielding of the heating means from surrounding environment is disclosed.

Foltyn, Steve R. (111 Beryl St., Los Alamos, NM 87544)

1996-01-01

393

Superconducting thin films on potassium tantalate substrates  

SciTech Connect

This patent describes a composition for the lossless transmission of electrical current, it comprises: a superconducting thin film epitaxially deposited on a oriented surface of a single crystal KTa{sub 1{minus}z}Nb{sub 2}O{sub 3} substrate, where z is 0 to 1, wherein the superconducting thin film is selected from the group consisting of YBa{sub 2{minus}}Cu{sub 3}O{sub 7}, Y{sub 2}Ba{sub 4}Cu{sub 8}O{sub 20}, a compound wherein a trivalent rare earth element replaces yttrium in compound YBa{sub 2}Cu{sub 3}O{sub 7}, and a compound wherein scandium replaces yttrium in the compound YBa{sub 2}Cu{sub 3}O{sub 7}.

Feenstra, R.; Boatner, L.A.

1992-05-05

394

Electrostatic Discharge Effects on Thin Film Resistors  

NASA Technical Reports Server (NTRS)

Recently, open circuit failures of individual elements in thin film resistor networks have been attributed to electrostatic discharge (ESD) effects. This paper will discuss the investigation that came to this conclusion and subsequent experimentation intended to characterize design factors that affect the sensitivity of resistor elements to ESD. The ESD testing was performed using the standard human body model simulation. Some of the design elements to be evaluated were: trace width, trace length (and thus width to length ratio), specific resistivity of the trace (ohms per square) and resistance value. However, once the experiments were in progress, it was realized that the ESD sensitivity of most of the complex patterns under evaluation was determined by other design and process factors such as trace shape and termination pad spacing. This paper includes pictorial examples of representative ESD failure sites, and provides some options for designing thin film resistors that are ESD resistant. The risks of ESD damage are assessed and handling precautions suggested.

Sampson, Michael J.; Hull, Scott M.

1999-01-01

395

PST thin films for electrocaloric coolers  

NASA Astrophysics Data System (ADS)

Relaxor behaviour in a thin film of partially ordered PbSc0.5Ta0.5O3 (PST) was confirmed via slim P-E loops and the frequency dependence of the temperature at which the dielectric constant is maximum. Indirect measurements of the electrocaloric effect suggest that removing a field of 774 kV cm-1 yields a temperature change of -3.5 C to -6.9 C over a broad range of operating temperatures near room temperature (1-127 C), with a correspondingly large refrigerant capacity of 662 J kg-1. In addition to low electrical hysteresis, there is negligible thermal hysteresis. PST thin films are therefore promising for EC cooling near room temperature.

Correia, T. M.; Kar-Narayan, S.; Young, J. S.; Scott, J. F.; Mathur, N. D.; Whatmore, R. W.; Zhang, Q.

2011-04-01

396

DNA Strand Patterns on Aluminium Thin Films  

PubMed Central

A new patterning method using Deoxyribose Nucleic Acid (DNA) strands capable of producing nanogaps of less than 100 nm is proposed and investigated in this work. DNA strands from Bosenbergia rotunda were used as the fundamental element in patterning DNA on thin films of aluminium (Al) metal without the need for any lithographic techniques. The DNA strands were applied in buffer solutions onto thin films of Al on silicon (Si) and the chemical interactions between the DNA strands and Al creates nanometer scale arbitrary patterning by direct transfer of the DNA strands onto the substrate. This simple and cost-effective method can be utilized in the fabrication of various components in electronic chips for microelectronics and Nano Electronic Mechanical System (NEMS) applications in general.

Khatir, Nadia Mahmoudi; Banihashemian, Seyedeh Maryam; Periasamy, Vengadesh; Majid, Wan Haliza Abd; Rahman, Saadah Abdul; Shahhosseini, Fatemeh

2011-01-01

397

Incoherent and laser photodeposition on thin films  

Microsoft Academic Search

High purity Zn, Se, and ZnSe thin films (approximately 100 to 6000A thicknesses) have been deposited on both quartz and sapphire substrates by using a Hg arc lamp u-v light source to photodissociate the organometallic molecules Zn(CH3)2 and Se(CH3)2. Large area depositions (approximately 1.5 cm diameter circles) have been produced, along with masked depositions created by selectively blocking the incoherent

W. E. Johnson

1980-01-01

398

Thin films of ruthenium phthalocyanine complexes  

Microsoft Academic Search

Four new ruthenium phthalocyanine complexes bearing axial ligands with thioacetate groups that facilitate thin film formation\\u000a on gold surfaces are presented. Scanning tunnelling microscopy (STM) images and surface coverage data obtained by solution\\u000a inductively coupled plasma mass spectrometry (ICP-MS) experiments show that peripheral and axial ligand substituents on the\\u000a complexes have a significant effect on their surface coverage. A laser

Tristan Rawling; Christine E. Austin; Dominic Hare; Philip A. Doble; Hadi M. Zareie; Andrew M. McDonagh

2009-01-01

399

Tin dioxide thin film hydrogen nanosensor  

Microsoft Academic Search

We present the results of investigations of double-layer thin-film hydrogen sensors that show high sensitivity at low operating temperatures and improved reliability. These hydrogen sensors are manufactured using the both ion-plasma assisted sputtering and sol-gel technique. It was established that the highest sensitivity of the sensors occurred at 100-130C. The hydrogen sensitivity depends on hydrogen concentration linearly starting at 50

V. M. Aroutiounian; A. Z. Adamyan; Z. N. Adamyan; A. H. Arakelyan

2008-01-01

400

Thin-film rupture for large slip  

Microsoft Academic Search

The rupture of thin liquid films on hydrophobic substrates, assuming large slip at the liquid-solid interface, is studied\\u000a using a recently developed strong slip lubrication model, it is shown that the rupture passes through up to three self-similar regimes with different dominant balances\\u000a and different scaling exponents. For one of these regimes the similarity is of second kind, and the

D. Peschka; A. Mnch; B. Niethammer

2010-01-01

401

Composite dilatometer for polymer thin films  

Microsoft Academic Search

A dilatometer is described for measuring volume changes in polymer thin films over a temperature range of 30150 C. The dilatometer is made entirely of glass, except for a stainless steel base and an aluminum clamp, which allow the sample chamber to be reusable. The dilatometer has the capability to measure volume changes in a 0.2 cm3 sample to within

Alan T. Parsons; C. M. Balik

1989-01-01

402

Experimental Mechanics of MEMS and Thin Films  

Microsoft Academic Search

\\u000a The novel thin film materials manufactured for MEMS sensors, actuators, and multifunctional coatings demand the development\\u000a of novel methodologies for the characterization of their anisotropic mechanical properties, which dominate as submicron sized\\u000a devices become technologically feasible. While the limitations of continuum mechanics are experimentally still unexplored,\\u000a material anisotropy and scale-dependence of deformations require a combined experimental, analytical, and numerical approach

Ioannis Chasiotis

403

Radiation Effect in Hexatriacontane Thin Film  

NASA Astrophysics Data System (ADS)

The secondary electron emission spectra of hexatriacontane thin film were measured as a function of irradiation time with an electron beam of about 19 eV. The spectral features which originate in the conduction band features in the crystalline state shifted to the low kinetic energy side linearly with the logarithm of the irradiation time. The shift is explained as an increase in the electron affinity due to the decomposition of hexatriacontane molecules.

Ueno, Nobuo; Sugita, Kazuyuki; Koga, Osamu; Suzuki, Shin

1983-10-01

404

Modeling structural metastability of irradiated thin films  

Microsoft Academic Search

The nucleation of crystalline or amorphous phases in irradiated binary metallic, as well as non-metallic compound thin films is interpreted using the atomistic interface migration-charge transfer (IMCT) model. The space and time evolution of dense collision cascades, which form upon ion bombardment of the target, lead to non-equilibrium compositional and electronic density profiles at the interface between each cascade and

P. M. Ossi

2004-01-01

405

Structures for dense, crack free thin films  

DOEpatents

The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); De Jonghe, Lutgard C. (Lafayette, CA)

2011-03-08

406

Optical properties of scandium thin films  

Microsoft Academic Search

A new investigation of the optical properties of scandium is presented. Near-normal-incidence reflectivity measurements were performed from 0.22 to 5.5 eV on polycrystalline thin films evaporated in situ in ultrahigh vacuum. The reflectivity, from 0.22 to 35 eV, of the same samples after they had been exposed to air was also measured. The ultraviolet reflectivity was affected by oxygen contamination

M. Sigrist; G. Chassaing; J. C. Franois; F. Antonangeli; N. Zema; M. Piacentini

1987-01-01

407

Thin Film Sensors for Surface Measurements  

NASA Technical Reports Server (NTRS)

Advanced thin film sensors that can provide accurate surface temperature, strain, and heat flux measurements have been developed at NASA Glenn Research Center. These sensors provide minimally intrusive characterization of advanced propulsion materials and components in hostile, high-temperature environments as well as validation of propulsion system design codes. The sensors are designed for applications on different material systems and engine components for testing in engine simulation facilities. Thin film thermocouples and strain gauges for the measurement of surface temperature and strain have been demonstrated on metals, ceramics and advanced ceramic-based composites of various component configurations. Test environments have included both air-breathing and space propulsion-based engine and burner rig environments at surface temperatures up to 1100 C and under high gas flow and pressure conditions. The technologies developed for these sensors as well as for a thin film heat flux gauge have been integrated into a single multifunctional gauge for the simultaneous real-time measurement of surface temperature, strain, and heat flux. This is the first step toward the development of smart sensors with integrated signal conditioning and high temperature electronics that would have the capability to provide feedback to the operating system in real-time. A description of the fabrication process for the thin film sensors and multifunctional gauge will be provided. In addition, the material systems on which the sensors have been demonstrated, the test facilities and the results of the tests to-date will be described. Finally, the results will be provided of the current effort to demonstrate the capabilities of the multifunctional gauge.

Martin, Lisa C.; Wrbanek, John D.; Fralick, Gustave C.

2001-01-01

408

Rechargeable thin-film lithium batteries  

SciTech Connect

Rechargeable thin-film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have recently been developed. The batteries, which are typically less than 6-{mu}m thick, can be fabricated to any specified size, large or small, onto a variety of substrates including ceramics, semiconductors, and plastics. The cells that have been investigated include Li-TiS{sub 2}, Li-V{sub 2}O{sub 5}, and Li-Li{sub x}Mn{sub 2}O{sub 4}, with open circuit voltages at full charge of about 2.5, 3.6, and 4.2, respectively. The development of these batteries would not have been possible without the discovery of a new thin-film lithium electrolyte, lithium phosphorus oxynitride, that is stable in contact with metallic lithium at these potentials. Deposited by rf magnetron sputtering of Li{sub 3}PO{sub 4} in N{sub 2}, this material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46} and a conductivity at 25{degrees}C of 2 {mu}S/cm. The maximum practical current density obtained from the thin-film cells is limited to about 100 {mu}A/cm{sup 2} due to a low diffusivity of Li{sup +} ions in the cathodes. In this work, the authors present a short review of their work on rechargeable thin-film lithium batteries.

Bates, J.B.; Gruzalski, G.R.; Dudney, N.J.; Luck, C.F.; Yu, Xiaohua

1993-08-01

409

Stable localized patterns in thin liquid films  

NASA Technical Reports Server (NTRS)

We study a 2-D nonlinear evolution equation which describes the 3-D spatiotemporal behavior of the air-liquid interface of a thin liquid film lying on the underside of a cooled horizontal plate. We show that the Marangoni effect can stabilize the destabilizing effect of gravity (the Rayleigh-Taylor instability) allowing for the existence of stable localized axisymmetric solutions for a wide range of parameter values. Various properties of these structures are discussed.

Deissler, Robert J.; Oron, Alexander

1991-01-01

410

Overview of current bulk and thick film high temperature superconductor processing strategies  

SciTech Connect

A review of processing strategies to prepare conductor-configured high temperature superconductors is presented along with a tabulation of recent results obtained using a variety of processing procedures to produce wires, tapes, monoliths, and thick films of high temperature superconducting material. 32 refs., 1 tab.

Ott, K.C.; Quinn, R.K.

1990-01-01

411

Thin films of magnetically doped topological insulators  

NASA Astrophysics Data System (ADS)

The interplay between the Dirac surface state and ferromagnetic order in topological insulators can lead to a number of very exotic quantum phenomena. To observe the quantum phenomena such as quantized anomalous Hall (QAH) effect in magnetically doped topological insulators, the materials are required to be in the form of thin film with tunable chemical potential and carrier-independent ferromagnetism. In this talk, I will report our recent progress in molecular beam epitaxy growth, chemical potential tuning and electronic properties of the magnetically doped topological insulator thin films. By Cr doping, we have realized both n-type and p-type conductivity in (BixSb1-x)2Te3 thin films. Remarkably their ferromagnetism was found independent of the type and concentration of carriers. Moreover, the anomalous Hall effect is significantly enhanced at low carrier concentration regime, with the anomalous Hall angle reaching an unusually large value of 0.2 and the zero field Hall resistance reaching one quarter of the quantum resistance (h/e2). These findings pave the way to ultimately observing the QAH effect and other quantum effects in magnetic topological insulators.

Chang, Cui-Zu

2012-02-01

412

Asymmetric grain distribution in phthalocyanine thin films  

SciTech Connect

Many electronic and optical properties of organic thin films depend on the precise morphology of grains. Iron phthalocyanine thin films are grown on sapphire substrates at different temperatures to study the effect of grain growth kinematics and to experimentally quantify the grain size distribution in organic thin films. The grain size is measured with an atomic force microscope and the data is processed and analyzed with well-known image segmentation algorithms. For relevant statistics, over 3000 grains are evaluated for each sample. The data show pronounced asymmetric grain growth with increasing deposition temperature from almost spherical grains at room temperature to elongated needlelike shapes at 260 deg. C. The average size along the major axis increases from 35 to 200 nm and along the minor axis from 25 to 90 nm. The distribution is almost symmetric at low-deposition temperatures, but becomes lognormal at higher temperatures. Strikingly, the major axis and minor axis of the elliptically shaped grains have different distributions at all temperatures due to the planar asymmetry of the molecule.

Gentry, K. Paul; Gredig, Thomas; Schuller, Ivan K. [Department of Physics and Astronomy, California State University-Long Beach, 1250 Bellflower Boulevard, Long Beach, California 90840 (United States); Department of Physics and Astronomy, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States)

2009-11-01

413

Hydrothermal epitaxy of perovskite thin films  

NASA Astrophysics Data System (ADS)

This work details the discovery and study of a new process for the growth of epitaxial single crystal thin films which we call hydrothermal epitaxy. Hydrothermal epitaxy is a low temperature solution route for producing heteroepitaxial thin films through the use of solution chemistry and structurally similar substrates. The application of this synthesis route has led to the growth of a variety of epitaxial perovskite (BaTiOsb3, SrTiOsb3, and Pb(Zr,Ti)Osb3 (PZT)) thin films which provides a simple processing pathway for the formation of other materials of technological interest. BaTiOsb3 and PZT heteroepitaxial thin films and powders were produced by the hydrothermal method at 90-200spC using various alkali bases. XRD and TEM analysis shows that, in each case, the films and powders form epitaxially with a composition nearly identical to that of the starting precursors. Sequential growth experiments show that film formation initiates by the nucleation of submicron faceted islands at the step edges of the SrTiOsb3 substrates followed by coalescence after longer growth periods. A Ba-rich interfacial layer between the BaTiOsb3 islands and the SrTiOsb3 surface is seen by cross-section TEM during early growth periods. Electrophoretic and Basp{2+} adsorption data provide a chemical basis for the existence of the interfacial layer. Homoepitaxial growth of SrTiOsb3 on SrTiOsb3 also occurs by island growth, suggesting that the growth mode may be a consequence of the aqueous surface chemistry inherent in the process. Film formation is shown to be affected by any number of factors including type of base, pH, temperature, and substrate pretreatments. Different cation bases (Na-, K-, Rb-, Cs-, TMA-OH) demonstrated pronounced changes in powder and film morphology. For example, smaller cation bases (e.g., NaOH, KOH and RbOH) resulted the formation of 1.5 mum \\{100\\} faceted perovskite PbTiOsb3 blocks while larger cation bases (e.g., CsOH and TMA-OH) produced 500 nm sized interpenetrating perovskite PbTiOsb3 platelets. The electrical properties of epitaxial BaTiOsb3 thin films formed on SrRuOsb3/SrTiOsb3 single crystal substrates were investigated by variable frequency dielectric testing. As-synthesized BaTiOsb3 films displayed high losses (varepsilon\\ 450, tan delta\\ 100% at 10kHz) with improvements detected with increasing heat treatment time and temperature (300spC, 24h, air, varepsilon\\ 200, tan delta\\ 8%). Proton and Hsb2O impurities were proposed to be the cause of the migration losses that contributed to the high dielectric loss within the film. FTIR, NMR, and TGA experiments were used to show the existence and quantity of OHsp- and Hsb2O impurities within and on the surface of the crystal lattice.

Chien, Allen T.

414

Thin Dielectric Films Containing Tb3+ Ions For Application In Thin Film Solar Cells  

NASA Astrophysics Data System (ADS)

Thin transparent dielectric films containing Tb3+ are developed for application as spectral converters of the solar spectrum in thin film silicon solar cells. The results on the deposition and characterization of thin SiO2 and Al2O3 films containing Tb3+ ions are presented. The films are prepared by RF magnetron co-sputtering, a well established technique for large area coatings. Photoluminescence (PL) is measured at room temperature, using the 488 nm line of an Ar laser and a nitrogen-cooled CCD camera attached to a monochromator. The dependence of the PL intensity on the concentration of Tb in the film is studied. It is found that the intensity exhibits a maximum at about 1 at.%. Annealing studies are performed on SiO2:Tb with two different methods to improve the PL intensity. In both regimes of annealing, the best results for thin SiO2:Tb films are obtained in the temperature range of 650-700 C. After treatment at this temperature the Tb PL increases 2.5-3 times.

Sendova-Vassileva, M.; Baumgartner, K.; Angelov, O.; Hollnder, B.; Dimova-Malmovska, D.; Carius, R.

2010-01-01

415

Polycrystalline Thin-Film Photovoltaic Technologies: Progress and Technical Issues  

SciTech Connect

Polycrystalline thin-film materials based on copper indium diselenide (CuInSe2, CIS) and cadmium telluride (CdTe) are promising thin-film solar cells for various power and specialty applications. Impressive results have been obtained in the past few years for both thin-film copper indium gallium diselenide (CIGS) solar cells and thin-film CdTe solar cells. NCPV/NREL scientists have achieved world-record, total-area efficiencies of 19.3% for a thin-film CIGS solar cell and 16.5% for thin-film CdTe solar cell. A number of technical R&D issues related to CIS and CdTe have been identified. Thin-film power module efficiencies up to 13.4% has been achieved thus far. Tremendous progress has been made in the technology development for module fabrication, and multi-megawatt manufacturing facilities are coming on line with expansion plans in the next few years. Several 40-480 kW polycrystalline thin-film, grid-connected PV arrays have been deployed worldwide. Hot and humid testing is also under way to validate the long-term reliability of these emerging thin-film power products. The U.S. thin-film production (amorphous silicon[a-Si], CIS, CdTe) is expected to exceed 50 MW by the end of 2005.

Ullal, H. S.

2004-08-01

416

Electrochromic molybdenum trioxide thin film preparation and characterization  

Microsoft Academic Search

Molybdenum trioxide is a very interesting material because it has applications in catalysis, in lithium batteries as cathode material, and in electrochromic devices. The authors laboratory has recently been interested in molybdenum trisulfide thin films obtained by electrodeposition from an aqueous solution of ammonium tetrathiomolybdate. The authors prepared molybdenum trioxide thin film coated tin oxide electrode from molybdenum sulfide thin

D. Belanger; G. Laperriere

2009-01-01

417

Texture development in BPSCCO superconductors  

SciTech Connect

After the discovery of bismuth-based superconductors, many attempts were made to develop high-density, sintered Bi-Pb-Sr-Ca-Cu-O (BPSCCO) ceramics having high current density (J{sub c}). Small coherence length, grain-boundary weak links and anisotropy of the high-critical-temperature (T{sub c}) cuprate grains of these superconductors caused lower J{sub c} values, even in epitaxially grown thin films. This report relates to an integrated approach for obtaining oriented microstructure in BPSCCO superconductor by combining two processing steps: viscous pressing (presintering process, PSP) and zone-melting refining (postsintering treatments, PST).

Mani, T.V.; Damodaran, A.D.; Warrier, K.G. [CSIR, Trivandrum (India)

1995-09-01

418

Comparison of the pinning energy in Fe(Se1?xTex) compound between single crystals and thin films  

NASA Astrophysics Data System (ADS)

Among the families of iron-based superconductors, we investigate flux pinning mechanisms in the Fe(Se1?xTex) compound. We perform magneto-resistance and current-voltage measurements on single-crystals, as well as on several epitaxial thin films grown on different substrates (CaF2, LaAlO3). The activation energy is derived as a function of magnetic field, U(H). The influence of magnetic field orientation on the pinning energy activation mechanism is also studied, leading to the anisotropy analysis which reveals low anisotropy in thin films grown on CaF2 substrate with respect to single crystals and films grown on LaAlO3. Concerning the dominant pinning regime, the exponents of the power law dependence U0(H) ~ H?? have been evaluated, confirm that weak pinning is a general characteristic of this compound. The single exponent feature, generally noticed on thin films grown on SrTiO3 substrate and associated to a strong single vortex regime, has been observed in thin films grown on LaAlO3, only in the parallel configuration. At the end, this overall comparison can be useful to develop a technological material able to compete with high temperature superconductors.

Leo, A.; Guarino, A.; Grimaldi, G.; Nigro, A.; Pace, S.; Bellingeri, E.; Kawale, S.; Ferdeghini, C.; Giannini, E.

2014-05-01

419

Magnetization Dynamics in Nickel Iron Thin Films  

NASA Astrophysics Data System (ADS)

The morphology, composition, and magnetic properties of NiFe thin films were characterized. Films with thicknesses up to 137 nm were deposited in an RF induction evaporator at high vacuum (10--8 mbar). Time resolved magneto-optic Kerr effect microscopy (TR-MOKE) was used to measure the Gilbert damping constant, an important dynamic magnetic property with applications to magnetic data storage. The composition of each film was measured with energy-dispersive X-ray (EDX) microscopy and used to determine the weight percent of Ni and Fe in each film. A trend of increased damping with increased thickness was found, in agreement with published results. Magnetic properties and roughness were found to differ significantly from previous films grown in the same vacuum chamber by Rudge, and are attributed to different growth modes produced by differing deposition conditions. However, the weight percent of Ni in each film was found to be inconsistent, deviating by up to 7% from the Ni80Fe20 evaporation source. Inconsistent composition, caused by the inability to control deposition parameters, prevents insight into Gilbert damping from being drawn from the analysis.

Santoni, Albert

420

Thin film cadmium telluride photovoltaic cells  

SciTech Connect

This report describes research to develop to vacuum-based growth techniques for CdTe thin-film solar cells: (1) laser-driven physical vapor deposition (LDPVD) and (2) radio-frequency (rf) sputtering. The LDPVD process was successfully used to deposit thin films of CdS, CdTe, and CdCl{sub 2}, as well as related alloys and doped semiconductor materials. The laser-driven deposition process readily permits the use of several target materials in the same vacuum chamber and, thus, complete solar cell structures were fabricated on SnO{sub 2}-coated glass using LDPVD. The rf sputtering process for film growth became operational, and progress was made in implementing it. Time was also devoted to enhancing or implementing a variety of film characterization systems and device testing facilities. A new system for transient spectroscopy on the ablation plume provided important new information on the physical mechanisms of LDPVD. The measurements show that, e.g., Cd is predominantly in the neutral atomic state in the plume but with a fraction that is highly excited internally ({ge} 6 eV), and that the typical neutral Cd translational kinetic energies perpendicular to the target are 20 eV and greater. 19 refs.

Compaan, A.; Bohn, R. (Toledo Univ., OH (United States))

1992-04-01

421

Semileaky thin-film optical isolator  

SciTech Connect

Two interesting effects have been experimentally demonstrated for the first time: (1) simultaneous reciprocal and nonreciprocal mode conversion to achieve an isolation effect and (2) magneto-optic switching between guided and radiation modes. These effects were observed in connection with the construction of a previously proposed thin-film optical isolator. The isolator consists of a piece of LiNbO/sub 3/ placed on top of a thin film of yttrium ion garnet (YIG) with a selenium layer to avoid optical contact problems. The isolator, which is 1 cm long, exhibited 10 dB of isolation at lambda = 1.15 ..mu..m. The observed isolation was better than theoretical predictions and a mysterious isolation direction dependence on mode order was observed. Although the device had 10 dB of insertion loss and required a magnetic field of 40 Oe, with a slight change in wavelength and film composition, it should be possible to reduce the insertion loss and field required to under 1 dB and 0.1 Oe, respectively. These characteristics combined with broad tolerances on film thickness and the length of the isolation region, broadband operation (from lambda = 1.1 to 4.5 ..mu..m), and easy construction and adjustment make the isolator very attractive for use in integrated optics.

Kirsch, S.T.; Biolsi, W.A.; Blank, S.L.; Tien, P.K.; Martin, R.J.; Bridenbaugh, P.M.; Grabbe, P.

1981-05-01

422

Study on infrared optical switching of vanadium dioxide thin film  

Microsoft Academic Search

Dispersion theory for refractive index and extinction coefficient of vanadium dioxide thin film is studied, and its temperature-dependence dispersion formula of optical constants is presented by numerical fitting with Sellmeier dispersion model. The optical transmittance and reflectance at different temperature and wavelength is calculated using film matrix theory. Vanadium dioxide thin films with different thickness are deposited by magnetron sputtering

Haifang Wang; Yi Li; Xiaojing Yu; Huiqun Zhu; Yize Huang; Hu Zhang; Wei Zhang

2009-01-01

423

Preparation of thin polymer films for infrared reaction rate studies  

NASA Technical Reports Server (NTRS)

Procedure for preparing thin films for infrared spectrophotometric analysis involves pressing of a neat mixture of reactants between nonreactive thin polymer films with noninterfering absorption bands. Pressing is done under a pressure that gives desirable thickness. Following this process, the film sandwich is cut to accommodate the laboratory instrument.

Garrard, G. G.; Houston, D. W.

1970-01-01

424

Switchable Mirror Thin Film for Energy Efficient Window  

Microsoft Academic Search

A new kind of energy efficient window using switchable mirror thin film which can be switched between mirror and transparent state freely is developed. Pd capped Mg6Ni thin film prepared by magnetron sputtering shows excellent switching property. By exposure to 4% H2 in Ar, the metallic film turns to a transparent state within a few seconds dramatically. A large size

Kazuki Yoshimura

2008-01-01

425

Phase diagrams of site diluted ferromagnetic thin film  

Microsoft Academic Search

The phase transition properties of Ising, classical XY and Heisenberg of diluted ferromagnetic thin film are studied by the method of exact high-temperature series expansions extrapolated with the Pad approximants method. The reduced critical temperature ?c of the diluted ferromagnetic thin films is studied as a function of film thickness L and the exchange interactions in the bulk Jb, in

M. Hamedoun; K. Bouslykhane; H. Bakrim; A. Hourmatallah; N. Benzakour; R. Masrour

2006-01-01

426

Multiple Charged Nitrogen Ion Beam Irradiation of Fullerene Thin Films  

Microsoft Academic Search

In this work, the results of structural modification of fullerene thin films bombarded by multiple charged nitrogen ions have been reported. The properties of as?deposited and irraditated fullerene thin films have been investigated by Raman and FTIR spectroscopy and AFM analysis. After irradiation by multiple charged nitrogen ions (N, N) new bondings in fullerene films have been formed and the

I. Dragani?; Z. Markovi?; Z. Stojanovi?; M. Mitri?; N. Rom?evi?; M. Rom?evi?; Z. Nikoli?

2007-01-01

427

Partial coherence theory of multilayer thin-film optical properties  

Microsoft Academic Search

Based on the theory of partially coherent light, an analytical scheme is established to determine the radiative properties of multilayer thin films. Accurate knowledge of the magnitude of interference effects is absolutely indispensable when measurements of the spectral transmissivity and reflectivity of thin films are used to derive optical constants of the film material. As illustrated by experiments, in many

Klaus Richter; Gang Chen; Chang-Lin Tien

1993-01-01

428

Electrohydrodynamic instabilities in thin trilayer liquid films.  

SciTech Connect

When DC or AC electric fields are applied to a thin liquid film, the interface may become unstable and form a series of pillars. We examine how the presence of a second liquid interface influences pillar dynamics and morphologies. For perfect dielectric films, linear stability analysis of a lubrication-approximation-based model shows that the root mean square voltage governs the pillar behavior. For leaky dielectric films, Floquet theory is applied to carry out the linear stability analysis, and reveals that the accumulation of free charge at each interface depends on the conductivities in the adjoining phases and that high frequencies of the AC electric field may be used to control this accumulation at each interface independently. The results presented here may of interest for the controlled creation of surface topographical features in applications such as patterned coatings and microelectronics.

Roberts, Scott A.; Kumar, Satish (University of Minnesota %3CU%2B2013%3E Twin Cities)

2010-11-01

429

Electrokinetic measurements of thin Nafion films.  

PubMed

We perform an electrokinetic characterization of ~300 nm Nafion films deposited on glass slides over a relatively unexplored region of ionic strength and pH. Owing to the small pore size of the Nafion, we probe the Nafion-fluid interface with the streaming potential measurement, and we probe ionic transport through the entire thickness of the Nafion film with the conductivity measurements. By applying a transport model for each of these measurements, we show that the inferred fixed charge density and characteristic fluid resistance length is different in each case. Analyzing our results with data from the literature, we suggest that our result is consistent with a thin Nafion film that is both nonuniform and weakly hydrated. Our regimen of experimentation and analysis may be generalized to characterize other porous and charged layers. PMID:24479374

Barbati, Alexander C; Kirby, Brian J

2014-03-01

430

Metal-doped magnetite thin films.  

PubMed

This paper investigates magnetite (Fe3O4) thin film containing a small amount of a metal element. The films are prepared by rf sputtering with a composite target of ceramic iron oxide with metal chips. Low-temperature magnetization of magnetite containing 5.3%Ge reveals that the film contains some magnetically weak coupling grains. The metal element Mg reduces both hematite (alpha-Fe2O3) and magnetite, resulting in single-phase wstite (Fe1-xO). In contrast, adding Ge selectively reduces hematite, while magnetite remains unreactive. According to the free energy of reaction, the element Ge is able to reduce hematite only, whereas the element Mg is capable of reducing both hematite and magnetite. This property is in good agreement with the experiment results. PMID:22905582

Abe, Seishi; Ping, De Hai; Nakamura, Shintaro; Ohnuma, Masato; Ohnuma, Shigehiro

2012-06-01

431

Fabrication and characterization of amorphous lithium electrolyte thin films and rechargeable thin-film batteries  

NASA Astrophysics Data System (ADS)

Amorphous oxide and oxynitride lithium electrolyte thin films were synthesized by r.f. magnetron sputtering of lithium silicates and lithium phosphates in Ar, Ar + O2, Ar + N2, or N2. The composition, structure, and electrical properties of the films were characterized using ion and electron beam, X ray, optical, photoelectron, and a.c. impedance techniques. For the lithium phosphosilicate films, lithium ion conductivities as high as 1.4 x 10(exp -6) S/cm at 25 C were observed, but none of these films selected for extended testing were stable in contact with lithium. On the other hand, a new thin-film lithium phosphorus oxynitride electrolyte, synthesized by sputtering Li3PO4 in pure N2, was found to have a conductivity of 2 x 10(exp -6) S/cm at 25 C and excellent long-term stability in contact with lithium. Thin-films cells consisting of a 1 micron thick amorphous V2O5 cathode, a 1 micron thick oxynitride electrolyte film, and a 5 micron thick lithium anode were cycled between 3.7 and 1.5 V using discharge rates of up to 100 mu A/sq cm and charge rates of up to 20 mu A/sq cm. The open-circuit voltage of 3.6 to 3.7 V of fully-charged cells remained virtually unchanged after months of storage.

Bates, J. B.; Dudney, N. J.; Gruzalski, G. R.; Zuhr, R. A.; Choudhury, A.; Luck, C. F.; Robertson, J. D.

1993-03-01

432

Dynamics of Bimodal Growth in Pentacene Thin Films  

SciTech Connect

Previous studies have established that pentacene films deposited on silicon oxide consist of a substrate-induced 'thin-film' phase, with the bulk phase of pentacene detected in thicker films only. We show that the bulk phase nucleates as early as the first monolayer, and continues to nucleate as film growth progresses, shadowing the growth of the thin-film phase. Moreover, we find that the transition between the 'thin-film' and the bulk phase is not a continuous one, as observed in heteroepitaxial systems, but rather the two phases nucleate and grow independently.

Mayer, Alex C.; Malliaras, George G. [Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Kazimirov, Alexander [Cornell High Energy Synchrotron Source, Ithaca, New York 14853 (United States)

2006-09-08

433

Novel approach for the analysis of the fluctuation magnetoconductivity in YBa 2Cu 3O 7 thin films  

Microsoft Academic Search

We report measurements of the paraconductivity and of the fluctuation magnetoconductivity as a function of both the magnetic field up to 13 T and the temperature in thin epitaxial films of YBa2Cu3O7. An analysis within the model for dirty-limit superconductors yields consistent values for the in-plane, the out-of-plane coherence lengths, and the quasiparticle phase coherence time. Although an estimation of

C. Sekirnjak; W. Lang; S. Proyer; P. Schwab

1995-01-01

434

Specific heat measurement set-up for quench condensed thin superconducting films  

NASA Astrophysics Data System (ADS)

We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films.

Poran, Shachaf; Molina-Ruiz, Manel; Grardin, Anne; Frydman, Aviad; Bourgeois, Olivier

2014-05-01

435

Specific heat measurement set-up for quench condensed thin superconducting films.  

PubMed

We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films. PMID:24880383

Poran, Shachaf; Molina-Ruiz, Manel; Grardin, Anne; Frydman, Aviad; Bourgeois, Olivier

2014-05-01

436

Video detection of microwaves using high- Tc Y-Ba-Cu-O thin films  

SciTech Connect

The high-temperature ceramic superconductors are granular in nature and contain several Josephson-type weak links limiting the critical current density in these materials. However, this granular superconductivity is successfully exploited by several researchers to realize some useful devices such as SQUIDs microwave detectors, and mixers at liquid-nitrogen temperature. In this communication the authors present some of the results on Video detection experiments at microwave frequencies using high-{Tc} YBCO granular thin films at 64 K. In this video mode the authors shall be interested in the output voltage from a current-biased Josephson junction that is subjected to a chopped single-frequency microwave signal.

Rao, V.V.; Mishra, S.K.; Pathak, L.C.; Subramaniam, R. (Indian Inst. of Tech., Karagpur (India))

1992-02-01

437

Thin film structures and phase stability  

SciTech Connect

This was a two day symposium, with invited and contributed papers as well as an evening poster session. The first day concentrated on solid state reactions with invited talks by Lindsay Greer from the University of Cambridge, King Tu from IBM Yorktown Heights, and Carl Thompson from MIT. Professor Greer observed that the diffusion of Zr is 10{sup 6} times slower than that of Ni in amorphous NiZr, confirming that Ni is the mobile species in solid state amorphization. King Tu explained the formation of metastable phases in this film diffusion couples by the concept of maximum rate of free energy change. Carl Thompson discussed the formation of amorphous phases in metal silicon systems, and discussed a two stage nucleation and growth process. The contributed papers also generated discussion on topics such as phase segregation, amorphous silicide formation, room temperature oxidation of silicon, and nucleation during ion beam irradiation. There was a lively poster session on Monday evening with papers on a wide variety of topics covering the general area of thin film science. The second day had sessions Epitaxy and Multilayer Structure I and II, with the morning focussing on epitaxial and heteroepitaxial growth of thin films. Robin Farrow of IBM Almaden led off with an invited talk where he reported on some remarkable success he and his co-workers have had in growing single crystal epitaxial thin films and superlattices of silver, iron, cobalt and platinum on GaAs. This was followed by several talks on epitaxial growth and characterization. The afternoon focused on interfaces and structure of multilayered materials. A session on possible stress origins of the supermodulus effect was highlighted by lively interaction from the audience. Most of the papers presented at the symposium are presented in this book.

Clemens, B.M. (Stanford Univ., CA (United States)); Johnson, W.L. (California Inst. of Tech., Pasadena, CA (United States))

1990-01-01

438

A sequential thin-film deposition equipment for in-situ fabricating all-solid-state thin film lithium batteries  

Microsoft Academic Search

To improve the interfacial quality and electrochemical performance of all-solid-state thin film lithium batteries (TFLBs), a sequential thin film deposition equipment has been developed. This equipment consists of a dry glove box for packing TFLB and four vacuum chambers, one chamber of them for deposition lithium film anode by flash thermal evaporation, and the other three vacuum chambers for deposition

Wen-Yuan Liu; Zheng-Wen Fu; Qi-Zong Qin

2007-01-01

439

Chemical Preparation of Powders and Films for High Temperature Superconductors.  

National Technical Information Service (NTIS)

A precipitation process has been developed to prepare precursor powders which can be calcined and sintered to form high critical temperature superconductors such as YBa sub 2 Cu sub 3 O/sub 7-x/. Precursor powders are prepared using a continuous precipita...

B. C. Bunker J. A. Voigt D. L. Lamppa D. H. Doughty E. L. Venturini

1988-01-01

440

Alternating current losses in superconductors of the second kind  

Microsoft Academic Search

The power (heating) losses occurring when an alternating current in a ; hard superconductor is used to produce a pulsed or alternating magnetic field are ; estimated. Heat losses for a solenoid are proportional to the conductor ; thickness, dictating the use of thin films for second-kind superconductors ; carrying alternating current. (D.C.W.);

1963-01-01

441

RF critical field measurement of MgB2 thin films coated on Nb  

NASA Astrophysics Data System (ADS)

Niobium (Nb) Superconducting RF (SRF) cavities have been used or will be used for a number of particle accelerators. The fundamental limit of the accelerating gradient has been thought to be around 50 MV/m due to its RF critical magnetic field of around 200 mT. This limit will prevent new projects requiring higher gradient and compact accelerators from considering SRF structures. There is a theory, however, that promises to overcome this limitation by coating thin (less than the penetration depth) superconductors on Nb. We initiated measurements of critical magnetic fields of Nb coated with various thin film superconductors, starting with MgB2 films deposited using reactive evaporation technique, with the goal to apply this coating to SRF cavities. This paper will present first test results of the RF critical magnetic field of a system consisting of a 10 nm B and a 100 nm MgB2 films deposited on a chemically polished 2-inch single grain Nb substrate.

Tajima, T.; Eremeev, G.; Zou, G.; Dolgashev, V.; Martin, D.; Nantista, C.; Tantawi, S.; Yoneda, C.; Moeckly, B. H.; Campisi, I.

2010-06-01

442

Fractional topological excitations and quantum phase transition in a bilayer two-dimensional electron gas adjacent to a superconductor film  

NASA Astrophysics Data System (ADS)

We study a bilayer two-dimension-electron-gas (2DEG) adjacent to a type-II superconductor thin film with a pinned vortex lattice. We find that with increasing interlayer tunneling, the system of half-filling presents three phases: gapped phase-I (topological insulator), gapless critical phase-II (metal), and gapped phase-III (band insulator). The total Hall conductance for phase-I/III is 2/0 e2/h , and has nonquantized values in phase-II. The excitation (response to topological defect, a local vortex defect) in these three phases shows different behaviors due to the topological property of the system, including fractional charge e/2 for each layer in phase-I. While in the case of quarter-filling, the system undergoes a quantum phase transition from metallic phase to topological insulator phase.

Hao, Ningning; Zhang, Wei; Wang, Zhigang; Wang, Yupeng; Zhang, Ping

2010-03-01

443

First Solar Polycrystalline CdTe Thin Film PV  

Microsoft Academic Search

First solar has been manufacturing and selling thin film PV modules commercially since 2002. The first solar FS series module product is a single-junction polycrystalline thin film structure that employs CdTe as the absorption layer and CdS as the window layer. First solar's production process uses thin film semiconductor technology that integrates the entire solar module manufacturing process into a

Peter V. Meyers

2006-01-01

444

Overview and Challenges of Thin Film Solar Electric Technologies  

SciTech Connect

In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

Ullal, H. S.

2008-12-01

445

Overview and Challenges of Thin Film Solar Electric Technologies  

Microsoft Academic Search

In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity

H. S. Ullal

2008-01-01

446

Nanostructured vanadium dioxide thin films with low phase transition temperature  

Microsoft Academic Search

A low phase turning temperature of 35 C has been observed in the semiconductor-to-metal transition of nanoscale vanadium dioxide (VO2) thin films. The thin films are prepared by reactive ion beam sputtering deposition and subsequent thermal annealing. Both scanning electron microscopy and transmission electron microscopy measurements show that the grain size of the fabricated VO2 thin films are several tens

Sihai Chen; Hong Ma; Jun Dai; Xinjian Yi

2007-01-01

447

Micromachined ultrasonic transducers with piezoelectric AlN thin films  

Microsoft Academic Search

In this research, a laboratory prototype of micromachined ultrasonic transducer (MUT) has been designed and fabricated with the application of piezoelectric aluminum nitride (AlN) thin films. The fabrication process of MUT device, especially the deposition of AlN thin film, is compatible with a standard integrated circuits (IC) technology. Preliminary results have demonstrated the feasibility of AlN thin film applied in

Qianghua Wang

2005-01-01

448

Micromachined ultrasonic transducers with piezoelectric aluminum nitride thin films  

Microsoft Academic Search

In this research, a laboratory prototype of micromachined ultrasonic transducer (MUT) has been designed and fabricated with the application of piezoelectric aluminum nitride (AlN) thin films. The fabrication process of MUT device, especially the deposition of AlN thin film, is compatible with a standard integrated circuits (IC) technology. Preliminary results have demonstrated the feasibility of AlN thin film applied in

Qianghua Wang

2005-01-01

449

Thermoluminescence of aluminum oxide thin films subject to ultraviolet irradiation  

Microsoft Academic Search

The thermoluminescence (TL) properties of amorphous aluminum oxide thin films subjected to ultraviolet (UV) irradiation are reported. Aluminum oxide thin films were prepared by laser ablation from an ?-Al2O3 target using Nd:YAG laser with emission at the fundamental line. Compositional, structural and morphological properties of the obtained thin films as a function of the growth conditions have been studied. Experimental

L. Escobar-Alarcn; E. Villagrn; E. Camps; S. Romero; J. E. Villarreal-Barajas; P. R. Gonzlez

2003-01-01

450

Hydrogen in obliquely deposited LaNi 5 thin films  

Microsoft Academic Search

During the last decade, thin film metal hydride has become an emerging field of research. The effect of hydrogen charging\\/discharging on the electrical resistance of obliquely deposited (?=0,30,45,60,75)LaNi_5 thin films of thickness 1300.5nm was investigated. It was found that the activation of LaNi_5 thin films for hydrogen absorption is fairly simple. The change in resistance due to hydrogen absorption increases

Babita Devi; M. Vashistha; I. P. Jain

2001-01-01

451

RELIABILITY OF BARIUM STRONTIUM TITANATE (BST) THIN FILMS  

Microsoft Academic Search

Ba0.6Sr0.4TiO3 (BST) thin films were deposited on Pt\\/Ti\\/LaAlO3 (100) substrates by radio-frequency magnetron sputtering. Not only the fatigue characteristic of BST thin film but also the temperature and frequency dependences of dielectric constant (?r), loss tangent (tan?) and tunability (at 300 kV\\/cm) were investigated. With the temperature increasing, the dielectric constant of BST thin film increases slowly and the fluctuation

HONGWEI CHEN; CHUANREN YANG; BO WANG; JIHUA ZHANG; AN YU

2009-01-01

452

Thin-Film Photovoltaic Radiation Testing for Space Applications  

Microsoft Academic Search

Although thin-film photovoltaic technology on lightweight flexible substrates has lower beginning-of-life efficiency compared to traditional single crystalline solar cells, it can offer advantages in high-specific power and low-stowed volume for power generation in space. To date, radiation testing on thin-film solar cells has demonstrated superior radiation hardness compared to traditional crystalline solar cells. In addition, radiation induced damage in thin-film

S. H. Liu; J. E. Granata; J. C. Nocerino; J. S. Halpine; E. J. Simburger

2006-01-01

453

Development of Flexible Electrochromic Device with Thin-Film Configuration  

Microsoft Academic Search

As we reported previously, the carrier accumulation mechanism is very useful for obtaining a quick-response electrochromic (EC) device with the inorganic-thin-film configuration. To confirm the availability of this concept for flexible substrates, the EC device has been fabricated on a polymeric film. The device is composed of a top semitransparent electrode, an electrolytic thin Ta2O5 film, a very thin SiO2

Hideo Yoshimura; Tomonori Sakaguchi; Nobuyoshi Koshida

2007-01-01

454

New Switchable Mirror Based on Magnesium-Niobium Thin Film  

Microsoft Academic Search

We found that palladium-capped magnesium-niobium alloy thin films show a good optical switching property when they are exposed to a hydrogen-containing atmosphere. A switchable mirror based on a magnesium-niobium thin film was prepared on a glass substrate by cosputtering of Mg and Nb targets. Mg1-xNbx thin films with a 4 nm Pd overlayer can be switched reversibly between shiny mirror

Shanhu Bao; Yasusei Yamada; Kazuki Tajima; Masahisa Okada; Kazuki Yoshimura

2007-01-01

455

Silicon films with gallium-rich nanoinclusions: from superconductor to insulator  

NASA Astrophysics Data System (ADS)

Si films sputter deposited on thermally oxidized Si are enriched with Ga by ion implantation through a SiO2 capping layer. The morphology and the electrical transport properties of these films are investigated after rapid thermal annealing. Amorphous, Ga-rich nanoinclusions are embedded in a nanocrystalline Si matrix. The metallic nanoinclusions become superconducting below 7 K. They form a random network of junctions to heavily doped Si crystallites. Small modifications of the junction properties, e.g. by annealing or current pulses, can dramatically change the electronic transport in the film. Ga-rich Si films show a wealth of low-temperature transport phenomena, which have been known until now only from granular metals or high-temperature superconductors: superconductor-insulator transition, quasi-reentrant superconductivity and current-controlled sheet resistance. The possibility to prepare and modify Ga-rich Si films with microelectronics-compatible technology makes them interesting for both fundamental research on transport phenomena in nanostructured, disordered superconductors as well as for the integration of superconducting circuits into Si devices.

Heera, V.; Fiedler, J.; Hbner, R.; Schmidt, B.; Voelskow, M.; Skorupa, W.; Skrotzki, R.; Herrmannsdrfer, T.; Wosnitza, J.; Helm, M.

2013-08-01

456

Pulsed laser deposition of pepsin thin films  

NASA Astrophysics Data System (ADS)

Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser ( ? = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm 2. The pressure in the PLD chamber was 2.7 10 -3 Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm 2. The protein digesting capacity of the transferred pepsin was tested by adapting a modified "protein cube" method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.

Kecskemti, G.; Kresz, N.; Smausz, T.; Hopp, B.; Ngrdi, A.

2005-07-01

457

Thin films of metal-organic frameworks.  

PubMed

The fabrication of thin film coatings of metal-organic frameworks (MOFs) on various substrates is discussed in this critical review. Interestingly, the relatively few studies on MOF films that have appeared in the literature are limited to the following cases: [Zn4O(bdc)3] (MOF-5; bdc=1,4-benzenedicarboxylate), [Cu3(btc)2] (HKUST-1; btc=1,3,5-benzenetricarboxylate), [Zn2(bdc)2(dabco)] (dabco=1,4-diazabicyclo[2.2.2]octane), [Mn(HCOO)], [Cu2(pzdc)2(pyz)] (CPL-1; pzdc=pyrazine-2,3-dicarboxylate, pyz=pyrazine), [Fe(OH)(bdc)] (MIL-53(Fe)) and [Fe3O(bdc)3(Ac)] (MIL-88B; Ac=CH3COO-). Various substrates and support materials have been used, including silica, porous alumina, graphite and organic surfaces, i.e. self-assembled monolayers (SAMs) on gold, as well as silica surfaces. Most of the MOF films were grown by immersion of the selected substrates into specifically pre-treated solvothermal mother liquors of the particular MOF material. This results in more or less densely packed films of intergrown primary crystallites of sizes ranging up to several microm, leading to corresponding film thicknesses. Alternatively, almost atomically flat and very homogenous films, with thicknesses of up to ca. 100 nm, were grown in a novel stepwise layer-by-layer method. The individual growth steps are separated by removing unreacted components via rinsing the substrate with the solvent. The layer-by-layer method offers the possibility to study the kinetics of film formation in more detail using surface plasmon resonance. In some cases, particularly on SAM-modified substrates, a highly oriented growth was observed, and in the case of the MIL-53/MIL-88B system, a phase selective deposition of MIL-88B, rather than MIL-53(Fe), was reported. The growth of MOF thin films is important for smart membranes, catalytic coatings, chemical sensors and related nanodevices (63 references). PMID:19384445

Zacher, Denise; Shekhah, Osama; Wll, Christof; Fischer, Roland A

2009-05-01

458

Physical Properties of Thin Film Semiconducting Materials  

NASA Astrophysics Data System (ADS)

The physics and chemistry of semiconducting materials is a continuous question of debate. We can find a large stock of well-known properties but at the same time, many things are not understood. In recent years, porous silicon (PS-Si), diselenide of copper and indium (CuInSe2 or CIS) and metal oxide semiconductors like tin oxide (SnO2) and zinc oxide (ZnO) have been subjected to extensive studies because of the rising interest their potential applications in fields such as electronic components, solar panels, catalysis, gas sensors, in biocompatible materials, in Li-based batteries, in new generation of MOSFETS. Bulk structure and surface and interface properties play important roles in all of these applications. A deeper understanding of these fundamental properties would impact largely on technological application performances. In our laboratory, thin films of undoped and antimony-doped films of tin oxide have been deposited by chemical vapor deposition. Spray pyrolysis was used for ZnO. CIS was prepared by flash evaporation or close-space vapor transport. Some of the deposition parameters have been varied, such as substrate temperature, time of deposition (or anodization), and molar concentration of bath preparation. For some samples, thermal annealing was carried out under oxygen (or air), under nitrogen gas and under vacuum. Deposition and post-deposition parameters are known to strongly influence film structure and electrical resistivity. We investigated the influence of film thickness and thermal annealing on structural optical and electrical properties of the films. Examination of SnO2 by x-ray diffraction showed that the main films are polycrystalline with rutile structure. The x-ray spectra of ZnO indicated a hexagonal wurtzite structure. Characterizations of CIS films with compositional analysis, x-ray diffraction, scanning microscopy, spectrophotometry, and photoluminescence were carried out.

Bouras, N.; Djebbouri, M.; Outemzabet, R.; Sali, S.; Zerrouki, H.; Zouaoui, A.; Kesri, N.

2005-10-01

459

Thin films fabricated from a nanoparticle beam  

NASA Astrophysics Data System (ADS)

As time advances, man has been able to control technology in finer and finer detail. The microelectronics era is an example of this, with control down to the micrometer. Experts agree that we may be entering a new era, controlling technology down to the nanometer. One aspect of such control is making materials in the nanometer range, i.e. nanoparticles. For this purpose, a new magnetron-sputtering gun, inert gas condensation, nanoparticle source has been designed, built, and tested. Films made from cobalt, nickel, tantalum, molybdenum, chromium, and aluminum have been investigated. Transmission Electron Microscope measurements done at the University of Illinois confirm the thin films are nanostructured. This was also confirmed by Atomic Force Microscope measurements made at the F.I.U. Thin Film Laboratory. Composition, optical and magnetic properties have been measured. In most cases, unique properties have been found that differ significantly from bulk properties. Rutherford Backscattering measurements done at the University of Illinois determined significant percentages of oxygen and carbon in the samples, possibly due to interactions with air. Because of this, optical properties are a composite of oxide, metal, and void properties. Magnetic materials were determined to have spin-glass properties below the irreversibility temperature and superparamagnetic properties above it. Indications of possible future uses for these nanostructured materials are discussed.

Griffiths, Peter David

460

Network behavior in thin film growth dynamics  

NASA Astrophysics Data System (ADS)

We present a network modeling approach for various thin film growth techniques that incorporates re-emitted particles due to the nonunity sticking coefficients. We model re-emission of a particle from one surface site to another one as a network link and generate a network model corresponding to the thin film growth. Monte Carlo simulations are used to grow films and dynamically track the trajectories of re-emitted particles. We performed simulations for normal incidence, oblique angle, and chemical vapor deposition (CVD) techniques. Each deposition method leads to a different dynamic evolution of surface morphology due to different sticking coefficients involved and different strength of shadowing effect originating from the obliquely incident particles. Traditional dynamic-scaling analysis on surface morphology cannot point to any universal behavior. On the other hand, our detailed network analysis reveals that there exist universal behaviors in degree distributions, weighted average degree versus degree, and distance distributions independent of the sticking coefficient used and sometimes even independent of the growth technique. We also observe that network traffic during high-sticking coefficient CVD and oblique-angle deposition occurs mainly among edges of the columnar structures formed while it is more uniform and short range among hills and valleys of small sticking coefficient CVD and normal-angle depositions that produce smoother surfaces.

Karabacak, T.; Guclu, H.; Yuksel, M.

2009-05-01

461

High- Tc thin-film magnetometer  

SciTech Connect

We have constructed and tested high-{Tc} magnetometers by coupling a high-{Tc} thin-film Superconducting QUantum Interference Device (SQUID) to two different high-{Tc} thin-film flux transformers. The SQUID was made from Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8+y} films grown on MgO, with junctions consisting of native grain boundaries. The flux transformers were made from YBa{sub 2}Cu{sub 3}O{sub 7-x}, and each had 10-turn input coils and a single-turn pickup loop. The first transformer, which was patterned with a combination of shadow masks and photolithography, yielded a magnetic field gain of about {minus}7.5, functioned up to 79 K, and gave a magnetic field sensitivity B{sub N} (10 Hz) {approx} 3.1 pT Hz{sup {minus}1/2}at 38 K. The second transformer, which was patterned entirely by photolithography, yielded a gain of about {minus}8.7, functioned up to 25 K, and had a sensitivity B{sub N} (10 Hz) {approx} 3.5 pT Hz{sup {minus}1/2} at 4.2 K. In both cases, the limiting noise arose in the SQUID. 10 refs., 5 figs., 1 tab.

Miklich, A.H.; Wellstood, F.C.; Kingston, J.J.; Clarke, J. (Lawrence Berkeley Lab., CA (USA)); Colclough, M.S. (Conductus, Inc., Sunnyvale, CA (USA)); Cardona, A.H.; Bourne, L.C.; Olson, W.L.; Eddy, M.M. (Superconductor Technologies, Inc., Santa Barbara, CA (USA))

1990-09-01

462

CCMR: Synthesis of Nanoporous Gold Thin Films  

NSDL National Science Digital Library

Starting with a gold alloy, it is possible to selectively etch away the non-gold element and obtain a tortuous porous network within the gold with pore widths ranging from just 20-4nm. The vast amount of void space makes for large surface areas of approximately 2 m²/g. This new material has found use in such applications as filters, biosensors, chemical catalysts, and ultra-capacitors. Through annealing, the size of these pores can be modified to fit the need of its particular application. Previous research has been done here at Cornell on nanoporous gold in the form of bulk films with of 200μm. However, the behavior of thin films of this material of just 200nm in thickness has not yet been studied extensively. The goal of this project was to come up with a way to create nanoporous gold thin films and to measure the effects of pore coarsening during annealing and the amount of silver remaining in the sample during the etching procedure.

Thiel, Andrew

2005-08-17

463

Fluorination of amorphous thin-film materials with xenon fluoride  

DOEpatents

A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

Weil, R.B.

1987-05-01

464

Monolayer and Thin Film Behaviour of Stereoregular Poly(Methacrylates).  

National Technical Information Service (NTIS)

Contents: Influence of the tacticity on the monolayer behavior of poly(methacrylates); Monolayer crystallization of isotactic PMMA; Epitaxial crystallization in thin films of isotactic PMMA using crystalline LB films; Stereocomplexation of isotactic and s...

R. H. G. Brinkhuis

1991-01-01

465

Multivariate classification of BPSG thin films using Mahalanobis distances.  

National Technical Information Service (NTIS)

Infrared absorption spectra of borophosphosilicate glass (BPSG) thin films were collected to develop a rapid classification method for determining if the films are within the desired specifications. Classification of samples into good and bad categories w...

S. Zhang J. E. Franke T. M. Niemczyk D. M. Haaland J. N. Cox

1995-01-01

466

Fluorination of amorphous thin-film materials with xenon fluoride  

DOEpatents

A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

Weil, Raoul B. (Haifa, IL) [Haifa, IL

1988-01-01

467

Polycrystalline Thin-Film Photovoltaic Technologies: Progress and Technical Issues  

Microsoft Academic Search

Polycrystalline thin-film materials based on copper indium diselenide (CuInSe2, CIS) and cadmium telluride (CdTe) are promising thin-film solar cells for various power and specialty applications. Impressive results have been obtained in the past few years for both thin-film copper indium gallium diselenide (CIGS) solar cells and thin-film CdTe solar cells. NCPV\\/NREL scientists have achieved world-record, total-area efficiencies of 19.3% for

Harin S. Ullal

2004-01-01

468

Hot carrier type exchange in inorganic electroluminescent thin films  

NASA Astrophysics Data System (ADS)

The authors have observed the hot carrier type (holes or electrons) exchange in rare-earth-ion-activated strontium thiogallate (SrGa2S4) thin films by measuring the transient electroluminescent wave forms of the devices having a single insulating thin film. Measured wave forms revealed that the green electroluminescence of europium activated SrGa2S4 thin film occurs due to hot hole excitation. In contrast, the blue electroluminescence of cerium activated SrGa2S4 thin film occurs due to hot electron excitation. Hence, the hot carrier type is exchanged by the different rare-earth-ion doping.

Tanaka, Katsu; Okamoto, Shinji

2006-11-01

469

Uncooled thin film pyroelectric IR detector with aerogel thermal isolation  

DOEpatents

A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. Pb(Zr.sub.0.4 Ti.sub.0.6)O.sub.3 thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550.degree. C.

Ruffner, Judith A. (Albuquerque, NM); Bullington, Jeff A. (Albuquerque, NM); Clem, Paul G. (Albuquerque, NM); Warren, William L. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Tuttle, Bruce A. (Albuquerque, NM); Schwartz, Robert W. (Seneca, SC)

1999-01-01